diff --git a/CHANGELOG.md b/CHANGELOG.md
index 15856b7..4183b75 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,15 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## 2.3.0 - 2019-07-13
+
+### Added
+- Added menu bar with option to save simulation result as image
+- Added slider for setting the probability of double scattering
+
+### Changed
+- Replaced Add Population and Remove Population texts with icons
+
 ## 2.2.0 - 2019-07-09
 
 ### Added
@@ -12,7 +21,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added possibility to add preset crystal populations
 
 ### Changed
-- Disabled "Add population" button when there is only one population in simulation
+- Disabled "Remove population" button when there is only one population in simulation
 - Added multiple crystal populations by default
 
 ## 2.1.1 - 2019-07-08
diff --git a/README.md b/README.md
index 14d4864..896c236 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-# HaloRay
+# HaloRay ![](images/hexagon_small.png)
 [![Build status](https://ci.appveyor.com/api/projects/status/5k9laekby84x2ex1/branch/develop?svg=true)](https://ci.appveyor.com/project/naavis/haloray/branch/develop)
 
 HaloRay simulates the reflection and refraction of sun light inside hexagonal
@@ -37,9 +37,14 @@ Here are some general settings for the whole simulation.
 - **Rays per frame:** Number of rays traced through individual crystals per
     rendered frame
   - If the user interface slows down a lot during rendering, lower this value
-  - On an NVIDIA GeForce GTX 1070 a good value seems to be 500 000 - 1 000 000
+  - On an NVIDIA GeForce GTX 1070 a good value seems to be around 500 000
   - The maximum value for this parameter may be limited by your GPU
 - **Maximum frames:** Simulation stops after rendering this many frames
+- **Double scattering:** Probability of a single light ray to scatter from two
+  different ice crystals
+  - Note that this slows down the simulation significantly!
+  - A value of 0.0 means no rays are scattered twice, and 1.0 means all rays
+    are scattered twice
 
 ### Crystal settings
 
@@ -139,6 +144,7 @@ resulting executable:
 - Qt5Core.dll
 - Qt5Widgets.dll
 - Qt5Gui.dll
+- Qt5Svg.dll
 
 You can also do this automatically with the
 [windeployqt](https://doc.qt.io/qt-5/windows-deployment.html) tool, which is
diff --git a/appveyor.yml b/appveyor.yml
index 6e3d3dc..fadf82b 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -1,9 +1,8 @@
-version: '2.2.0-{build}'
+version: '2.3.0-{build}'
 branches:
   only:
     - master
     - develop
-    - /release\/.+/
 image: Visual Studio 2017
 clone_depth: 1
 environment:
diff --git a/images/hexagon_small.png b/images/hexagon_small.png
new file mode 100644
index 0000000..b2f7408
Binary files /dev/null and b/images/hexagon_small.png differ
diff --git a/src/gui/addCrystalPopulationButton.cpp b/src/gui/addCrystalPopulationButton.cpp
index 6759a7d..02d0dcf 100644
--- a/src/gui/addCrystalPopulationButton.cpp
+++ b/src/gui/addCrystalPopulationButton.cpp
@@ -3,15 +3,13 @@
 AddCrystalPopulationButton::AddCrystalPopulationButton(QWidget *parent)
     : QToolButton(parent)
 {
-    setSizePolicy(QSizePolicy::Policy::Expanding, QSizePolicy::Policy::Expanding);
-
     mMenu = new QMenu(this);
 
-    mAddRandom = new QAction("Add random", this);
-    mAddPlate = new QAction("Add plate", this);
-    mAddColumn = new QAction("Add column", this);
-    mAddParry = new QAction("Add Parry", this);
-    mAddLowitz = new QAction("Add Lowitz", this);
+    mAddRandom = new QAction(tr("Add random"), this);
+    mAddPlate = new QAction(tr("Add plate"), this);
+    mAddColumn = new QAction(tr("Add column"), this);
+    mAddParry = new QAction(tr("Add Parry"), this);
+    mAddLowitz = new QAction(tr("Add Lowitz"), this);
 
     mMenu->addActions({mAddRandom,
                        mAddPlate,
@@ -20,7 +18,8 @@ AddCrystalPopulationButton::AddCrystalPopulationButton(QWidget *parent)
                        mAddLowitz});
 
     setPopupMode(QToolButton::ToolButtonPopupMode::MenuButtonPopup);
-    setText("Add population");
+    setIcon(QIcon::fromTheme("list-add"));
+
     setMenu(mMenu);
 
     connect(this, &AddCrystalPopulationButton::clicked, [this]() { emit addPopulation(HaloSim::CrystalPopulationPreset::Random); });
diff --git a/src/gui/crystalSettingsWidget.cpp b/src/gui/crystalSettingsWidget.cpp
index 97615ab..268bcf9 100644
--- a/src/gui/crystalSettingsWidget.cpp
+++ b/src/gui/crystalSettingsWidget.cpp
@@ -4,7 +4,7 @@
 #include "../simulation/crystalPopulation.h"
 
 CrystalSettingsWidget::CrystalSettingsWidget(std::shared_ptr<HaloSim::CrystalPopulationRepository> crystalRepository, QWidget *parent)
-    : QGroupBox("Crystal settings", parent),
+    : QGroupBox("Crystal population settings", parent),
       mModel(new CrystalModel(crystalRepository)),
       mNextPopulationId(1)
 {
@@ -66,7 +66,7 @@ CrystalSettingsWidget::CrystalSettingsWidget(std::shared_ptr<HaloSim::CrystalPop
         updateRemovePopulationButtonState();
     });
 
-    connect(mRemovePopulationButton, &QPushButton::clicked, [this]() {
+    connect(mRemovePopulationButton, &QToolButton::clicked, [this]() {
         int index = mMapper->currentIndex();
         if (index == 0)
             mMapper->toNext();
@@ -112,73 +112,66 @@ void CrystalSettingsWidget::setupUi()
     mPopulationComboBox->setDuplicatesEnabled(true);
 
     mAddPopulationButton = new AddCrystalPopulationButton();
-    mAddPopulationButton->setMinimumHeight(30);
+    mAddPopulationButton->setIconSize(QSize(24, 24));
 
-    mRemovePopulationButton = new QPushButton("Remove population");
-    mRemovePopulationButton->setMinimumHeight(30);
-    mRemovePopulationButton->setStyleSheet("padding: 10px;");
+    mRemovePopulationButton = new QToolButton();
+    mRemovePopulationButton->setIcon(QIcon::fromTheme("list-remove"));
+    mRemovePopulationButton->setIconSize(QSize(24, 24));
 
     mCaRatioSlider = new SliderSpinBox(0.0, 15.0);
 
     mCaRatioStdSlider = new SliderSpinBox(0.0, 10.0);
 
     mTiltDistributionComboBox = new QComboBox();
-    mTiltDistributionComboBox->addItems({"Uniform", "Gaussian"});
+    mTiltDistributionComboBox->addItems({tr("Uniform"), tr("Gaussian")});
 
-    mTiltAverageLabel = new QLabel("Average");
-    mTiltAverageSlider = createAngleSlider(0.0, 180.0);
+    mTiltAverageLabel = new QLabel(tr("Average"));
+    mTiltAverageSlider = SliderSpinBox::createAngleSlider(0.0, 180.0);
 
-    mTiltStdLabel = new QLabel("Standard deviation");
-    mTiltStdSlider = createAngleSlider(0.0, 360.0);
+    mTiltStdLabel = new QLabel(tr("Standard deviation"));
+    mTiltStdSlider = SliderSpinBox::createAngleSlider(0.0, 360.0);
 
     mRotationDistributionComboBox = new QComboBox();
-    mRotationDistributionComboBox->addItems({"Uniform", "Gaussian"});
+    mRotationDistributionComboBox->addItems({tr("Uniform"), tr("Gaussian")});
 
-    mRotationAverageLabel = new QLabel("Average");
-    mRotationAverageSlider = createAngleSlider(0.0, 180.0);
+    mRotationAverageLabel = new QLabel(tr("Average"));
+    mRotationAverageSlider = SliderSpinBox::createAngleSlider(0.0, 180.0);
 
-    mRotationStdLabel = new QLabel("Standard deviation");
-    mRotationStdSlider = createAngleSlider(0.0, 360.0);
+    mRotationStdLabel = new QLabel(tr("Standard deviation"));
+    mRotationStdSlider = SliderSpinBox::createAngleSlider(0.0, 360.0);
 
     mWeightSpinBox = new QSpinBox();
     mWeightSpinBox->setMinimum(0);
     mWeightSpinBox->setMaximum(10000);
 
     auto mainLayout = new QFormLayout(this);
-    mainLayout->addRow("Crystal population", mPopulationComboBox);
 
     auto populationButtonLayout = new QHBoxLayout();
+    populationButtonLayout->addWidget(mPopulationComboBox);
     populationButtonLayout->addWidget(mAddPopulationButton);
     populationButtonLayout->addWidget(mRemovePopulationButton);
 
     mainLayout->addRow(populationButtonLayout);
-    mainLayout->addRow("Population weight", mWeightSpinBox);
+    mainLayout->addRow(tr("Population weight"), mWeightSpinBox);
     mainLayout->addItem(new QSpacerItem(0, 10));
-    mainLayout->addRow("C/A ratio average", mCaRatioSlider);
-    mainLayout->addRow("C/A ratio std.", mCaRatioStdSlider);
+    mainLayout->addRow(tr("C/A ratio average"), mCaRatioSlider);
+    mainLayout->addRow(tr("C/A ratio std."), mCaRatioStdSlider);
 
-    auto tiltGroupBox = new QGroupBox("C-axis tilt");
+    auto tiltGroupBox = new QGroupBox(tr("C-axis tilt"));
     auto tiltLayout = new QFormLayout(tiltGroupBox);
     mainLayout->addRow(tiltGroupBox);
-    tiltLayout->addRow("Distribution", mTiltDistributionComboBox);
+    tiltLayout->addRow(tr("Distribution"), mTiltDistributionComboBox);
     tiltLayout->addRow(mTiltAverageLabel, mTiltAverageSlider);
     tiltLayout->addRow(mTiltStdLabel, mTiltStdSlider);
 
-    auto rotationGroupBox = new QGroupBox("Rotation around C-axis");
+    auto rotationGroupBox = new QGroupBox(tr("Rotation around C-axis"));
     auto rotationLayout = new QFormLayout(rotationGroupBox);
     mainLayout->addRow(rotationGroupBox);
-    rotationLayout->addRow("Distribution", mRotationDistributionComboBox);
+    rotationLayout->addRow(tr("Distribution"), mRotationDistributionComboBox);
     rotationLayout->addRow(mRotationAverageLabel, mRotationAverageSlider);
     rotationLayout->addRow(mRotationStdLabel, mRotationStdSlider);
 }
 
-SliderSpinBox *CrystalSettingsWidget::createAngleSlider(double min, double max)
-{
-    auto slider = new SliderSpinBox(min, max);
-    slider->setSuffix("°");
-    return slider;
-}
-
 void CrystalSettingsWidget::setTiltVisibility(bool visible)
 {
     mTiltAverageSlider->setVisible(visible);
diff --git a/src/gui/crystalSettingsWidget.h b/src/gui/crystalSettingsWidget.h
index 4c98075..4f11af2 100644
--- a/src/gui/crystalSettingsWidget.h
+++ b/src/gui/crystalSettingsWidget.h
@@ -3,7 +3,7 @@
 #include <QGroupBox>
 #include <QComboBox>
 #include <QLabel>
-#include <QPushButton>
+#include <QToolButton>
 #include <QSpinBox>
 #include <QDataWidgetMapper>
 #include "addCrystalPopulationButton.h"
@@ -31,7 +31,7 @@ class CrystalSettingsWidget : public QGroupBox
     void setRotationVisibility(bool);
 
     AddCrystalPopulationButton *mAddPopulationButton;
-    QPushButton *mRemovePopulationButton;
+    QToolButton *mRemovePopulationButton;
 
     SliderSpinBox *mCaRatioSlider;
     SliderSpinBox *mCaRatioStdSlider;
diff --git a/src/gui/generalSettingsWidget.cpp b/src/gui/generalSettingsWidget.cpp
index acf8561..646c593 100644
--- a/src/gui/generalSettingsWidget.cpp
+++ b/src/gui/generalSettingsWidget.cpp
@@ -7,31 +7,35 @@ GeneralSettingsWidget::GeneralSettingsWidget(QWidget *parent)
     setupUi();
 
     connect(mSunAltitudeSlider, &SliderSpinBox::valueChanged, [this]() {
-        lightSourceChanged(stateToLightSource());
+        emit lightSourceChanged(stateToLightSource());
     });
 
     connect(mSunDiameterSpinBox, QOverload<double>::of(&QDoubleSpinBox::valueChanged), [this]() {
-        lightSourceChanged(stateToLightSource());
+        emit lightSourceChanged(stateToLightSource());
     });
 
     connect(mRaysPerFrameSpinBox, QOverload<int>::of(&QSpinBox::valueChanged), [this](int value) {
-        numRaysChanged((unsigned int)value);
+        emit numRaysChanged((unsigned int)value);
     });
 
     connect(mMaximumFramesSpinBox, QOverload<int>::of(&QSpinBox::valueChanged), [this](int value) {
-        maximumNumberOfIterationsChanged((unsigned int)value);
+        emit maximumNumberOfIterationsChanged((unsigned int)value);
     });
+
+    connect(mMultipleScattering, &SliderSpinBox::valueChanged, this, &GeneralSettingsWidget::multipleScatteringProbabilityChanged);
 }
 
 void GeneralSettingsWidget::setInitialValues(double sunDiameter,
                                              double sunAltitude,
                                              unsigned int raysPerFrame,
-                                             unsigned int maxNumFrames)
+                                             unsigned int maxNumFrames,
+                                             double multipleScatteringProbability)
 {
     mSunDiameterSpinBox->setValue(sunDiameter);
     mSunAltitudeSlider->setValue(sunAltitude);
     mRaysPerFrameSpinBox->setValue(raysPerFrame);
     mMaximumFramesSpinBox->setValue(maxNumFrames);
+    mMultipleScattering->setValue(multipleScatteringProbability);
 }
 
 void GeneralSettingsWidget::setupUi()
@@ -39,10 +43,7 @@ void GeneralSettingsWidget::setupUi()
     setMaximumWidth(400);
 
     mSunAltitudeSlider = new SliderSpinBox();
-    mSunAltitudeSlider->setSuffix("­°");
-    mSunAltitudeSlider->setMinimum(-90.0);
-    mSunAltitudeSlider->setMaximum(90.0);
-    mSunAltitudeSlider->setValue(0.0);
+    mSunAltitudeSlider = SliderSpinBox::createAngleSlider(-90.0, 90.0);
 
     mSunDiameterSpinBox = new QDoubleSpinBox();
     mSunDiameterSpinBox->setSuffix("­°");
@@ -65,11 +66,16 @@ void GeneralSettingsWidget::setupUi()
     mMaximumFramesSpinBox->setValue(100000000);
     mMaximumFramesSpinBox->setGroupSeparatorShown(true);
 
+    mMultipleScattering = new SliderSpinBox();
+    mMultipleScattering->setMinimum(0.0);
+    mMultipleScattering->setMaximum(1.0);
+
     auto layout = new QFormLayout(this);
-    layout->addRow("Sun altitude", mSunAltitudeSlider);
-    layout->addRow("Sun diameter", mSunDiameterSpinBox);
-    layout->addRow("Rays per frame", mRaysPerFrameSpinBox);
-    layout->addRow("Maximum frames", mMaximumFramesSpinBox);
+    layout->addRow(tr("Sun altitude"), mSunAltitudeSlider);
+    layout->addRow(tr("Sun diameter"), mSunDiameterSpinBox);
+    layout->addRow(tr("Rays per frame"), mRaysPerFrameSpinBox);
+    layout->addRow(tr("Maximum frames"), mMaximumFramesSpinBox);
+    layout->addRow(tr("Double scattering"), mMultipleScattering);
 }
 
 HaloSim::LightSource GeneralSettingsWidget::stateToLightSource() const
diff --git a/src/gui/generalSettingsWidget.h b/src/gui/generalSettingsWidget.h
index 8d4e909..0ecf1c7 100644
--- a/src/gui/generalSettingsWidget.h
+++ b/src/gui/generalSettingsWidget.h
@@ -14,12 +14,14 @@ class GeneralSettingsWidget : public QGroupBox
     void setInitialValues(double sunDiameter,
                           double sunAltitude,
                           unsigned int raysPerFrame,
-                          unsigned int maxNumFrames);
+                          unsigned int maxNumFrames,
+                          double multipleScatteringProbability);
 
 signals:
     void lightSourceChanged(HaloSim::LightSource light);
     void numRaysChanged(unsigned int rays);
     void maximumNumberOfIterationsChanged(unsigned int iterations);
+    void multipleScatteringProbabilityChanged(double probability);
 
 public slots:
     void toggleMaxIterationsSpinBoxStatus();
@@ -33,4 +35,5 @@ public slots:
     QDoubleSpinBox *mSunDiameterSpinBox;
     QSpinBox *mRaysPerFrameSpinBox;
     QSpinBox *mMaximumFramesSpinBox;
+    SliderSpinBox *mMultipleScattering;
 };
diff --git a/src/gui/mainWindow.cpp b/src/gui/mainWindow.cpp
index 0a7d4ba..783b58f 100644
--- a/src/gui/mainWindow.cpp
+++ b/src/gui/mainWindow.cpp
@@ -6,6 +6,11 @@
 #include <QString>
 #include <QScrollBar>
 #include <QIcon>
+#include <QMenu>
+#include <QMenuBar>
+#include <QApplication>
+#include <QFileDialog>
+#include <QDateTime>
 #include "../simulation/crystalPopulation.h"
 #include "sliderSpinBox.h"
 
@@ -14,6 +19,10 @@
 
 MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent)
 {
+#if _WIN32
+    QIcon::setThemeName("HaloRayTheme");
+#endif
+
     mCrystalRepository = std::make_shared<HaloSim::CrystalPopulationRepository>();
 
     /*
@@ -64,11 +73,34 @@ MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent)
     });
     connect(mGeneralSettingsWidget, &GeneralSettingsWidget::maximumNumberOfIterationsChanged, mOpenGLWidget, &OpenGLWidget::setMaxIterations);
     connect(mGeneralSettingsWidget, &GeneralSettingsWidget::maximumNumberOfIterationsChanged, mProgressBar, &QProgressBar::setMaximum);
+    connect(mGeneralSettingsWidget, &GeneralSettingsWidget::multipleScatteringProbabilityChanged, [this](double value) {
+        mEngine->setMultipleScatteringProbability(value);
+    });
 
     mGeneralSettingsWidget->setInitialValues(mEngine->getLightSource().diameter,
                                              mEngine->getLightSource().altitude,
                                              mEngine->getRaysPerStep(),
-                                             600);
+                                             600,
+                                             mEngine->getMultipleScatteringProbability());
+
+    // Signals for menu bar
+    connect(mQuitAction, &QAction::triggered, QApplication::instance(), &QApplication::quit);
+    connect(mSaveImageAction, &QAction::triggered, [this]() {
+        auto image = mOpenGLWidget->grabFramebuffer();
+        auto currentTime = QDateTime::currentDateTimeUtc().toString(Qt::DateFormat::ISODate);
+        auto defaultFilename = QString("haloray_%1.png")
+                                   .arg(currentTime)
+                                   .replace(":", "-");
+        QString filename = QFileDialog::getSaveFileName(this,
+                                                        tr("Save File"),
+                                                        defaultFilename,
+                                                        tr("Images (*.png)"));
+
+        if (!filename.isNull())
+        {
+            image.save(filename, "PNG", 50);
+        }
+    });
 }
 
 void MainWindow::setupUi()
@@ -83,6 +115,8 @@ void MainWindow::setupUi()
 
     setWindowIcon(QIcon(":/haloray.ico"));
 
+    setupMenuBar();
+
     mOpenGLWidget = new OpenGLWidget();
     mProgressBar = setupProgressBar();
     mRenderButton = new RenderButton();
@@ -101,6 +135,14 @@ void MainWindow::setupUi()
     topLayout->addWidget(mOpenGLWidget);
 }
 
+void MainWindow::setupMenuBar()
+{
+    auto fileMenu = menuBar()->addMenu(tr("&File"));
+    mSaveImageAction = fileMenu->addAction(tr("Save image"));
+    fileMenu->addSeparator();
+    mQuitAction = fileMenu->addAction(tr("&Quit"));
+}
+
 QScrollArea *MainWindow::setupSideBarScrollArea()
 {
     mGeneralSettingsWidget = new GeneralSettingsWidget();
diff --git a/src/gui/mainWindow.h b/src/gui/mainWindow.h
index e1b5e9d..c1998df 100644
--- a/src/gui/mainWindow.h
+++ b/src/gui/mainWindow.h
@@ -4,6 +4,7 @@
 #include <QDoubleSpinBox>
 #include <QProgressBar>
 #include <QScrollArea>
+#include <QAction>
 #include <memory>
 #include "renderButton.h"
 #include "openGLWidget.h"
@@ -25,6 +26,7 @@ class MainWindow : public QMainWindow
     void setupUi();
     QScrollArea *setupSideBarScrollArea();
     QProgressBar *setupProgressBar();
+    void setupMenuBar();
 
     GeneralSettingsWidget *mGeneralSettingsWidget;
     CrystalSettingsWidget *mCrystalSettingsWidget;
@@ -33,6 +35,9 @@ class MainWindow : public QMainWindow
     RenderButton *mRenderButton;
     OpenGLWidget *mOpenGLWidget;
 
+    QAction *mSaveImageAction;
+    QAction *mQuitAction;
+
     std::shared_ptr<HaloSim::CrystalPopulationRepository> mCrystalRepository;
     std::shared_ptr<HaloSim::SimulationEngine> mEngine;
 };
diff --git a/src/gui/renderButton.cpp b/src/gui/renderButton.cpp
index 7f29676..544cd8e 100644
--- a/src/gui/renderButton.cpp
+++ b/src/gui/renderButton.cpp
@@ -4,8 +4,8 @@
 RenderButton::RenderButton(QWidget *parent)
     : QPushButton(parent), mRendering(false)
 {
-    const QString renderText = "Render";
-    const QString stopText = "Stop";
+    const QString renderText = tr("Render");
+    const QString stopText = tr("Stop");
 
     setText(renderText);
     setStyleSheet("font: bold;");
diff --git a/src/gui/sliderSpinBox.cpp b/src/gui/sliderSpinBox.cpp
index d873114..a930fa5 100644
--- a/src/gui/sliderSpinBox.cpp
+++ b/src/gui/sliderSpinBox.cpp
@@ -66,3 +66,10 @@ double SliderSpinBox::value() const
 {
     return mSpinBox->value();
 }
+
+SliderSpinBox *SliderSpinBox::createAngleSlider(double min, double max)
+{
+    auto slider = new SliderSpinBox(min, max);
+    slider->setSuffix("°");
+    return slider;
+}
diff --git a/src/gui/sliderSpinBox.h b/src/gui/sliderSpinBox.h
index 3d329a3..f8a4488 100644
--- a/src/gui/sliderSpinBox.h
+++ b/src/gui/sliderSpinBox.h
@@ -14,6 +14,8 @@ class SliderSpinBox : public QWidget
     void setSuffix(const QString &suffix);
     double value() const;
 
+    static SliderSpinBox *createAngleSlider(double min, double max);
+
 public slots:
     void setValue(double value);
     void setMinimum(double minimum);
diff --git a/src/gui/viewSettingsWidget.cpp b/src/gui/viewSettingsWidget.cpp
index 4382109..c1e4765 100644
--- a/src/gui/viewSettingsWidget.cpp
+++ b/src/gui/viewSettingsWidget.cpp
@@ -27,27 +27,18 @@ void ViewSettingsWidget::setupUi()
     setMaximumWidth(400);
 
     mCameraProjectionComboBox = new QComboBox();
-    mCameraProjectionComboBox->addItems({"Stereographic",
-                                         "Rectilinear",
-                                         "Equidistant",
-                                         "Equal area",
-                                         "Orthographic"});
-
-    mPitchSlider = new SliderSpinBox();
-    mPitchSlider->setMinimum(-90.0);
-    mPitchSlider->setMaximum(90.0);
-    mPitchSlider->setSuffix("°");
-
-    mYawSlider = new SliderSpinBox();
-    mYawSlider->setMinimum(-360.0);
-    mYawSlider->setMaximum(360.0);
+    mCameraProjectionComboBox->addItems({tr("Stereographic"),
+                                         tr("Rectilinear"),
+                                         tr("Equidistant"),
+                                         tr("Equal area"),
+                                         tr("Orthographic")});
+
+    mPitchSlider = SliderSpinBox::createAngleSlider(-90.0, 90.0);
+
+    mYawSlider = SliderSpinBox::createAngleSlider(-360.0, 360.0);
     mYawSlider->setWrapping(true);
-    mYawSlider->setSuffix("°");
 
-    mFieldOfViewSlider = new SliderSpinBox();
-    mFieldOfViewSlider->setMinimum(10.0);
-    mFieldOfViewSlider->setMaximum(360.0);
-    mFieldOfViewSlider->setSuffix("°");
+    mFieldOfViewSlider = SliderSpinBox::createAngleSlider(10.0, 360.0);
 
     mBrightnessSlider = new SliderSpinBox();
     mBrightnessSlider->setMinimum(0.1);
@@ -58,13 +49,13 @@ void ViewSettingsWidget::setupUi()
     mLockToLightSource = new QCheckBox();
 
     auto layout = new QFormLayout(this);
-    layout->addRow("Camera projection", mCameraProjectionComboBox);
-    layout->addRow("Field of view", mFieldOfViewSlider);
-    layout->addRow("Pitch", mPitchSlider);
-    layout->addRow("Yaw", mYawSlider);
-    layout->addRow("Brightness", mBrightnessSlider);
-    layout->addRow("Hide sub-horizon", mHideSubHorizonCheckBox);
-    layout->addRow("Lock to light source", mLockToLightSource);
+    layout->addRow(tr("Camera projection"), mCameraProjectionComboBox);
+    layout->addRow(tr("Field of view"), mFieldOfViewSlider);
+    layout->addRow(tr("Pitch"), mPitchSlider);
+    layout->addRow(tr("Yaw"), mYawSlider);
+    layout->addRow(tr("Brightness"), mBrightnessSlider);
+    layout->addRow(tr("Hide sub-horizon"), mHideSubHorizonCheckBox);
+    layout->addRow(tr("Lock to light source"), mLockToLightSource);
 }
 
 HaloSim::Camera ViewSettingsWidget::stateToCamera() const
diff --git a/src/main.cpp b/src/main.cpp
index f60ebdd..10f2c8a 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -43,5 +43,7 @@ int main(int argc, char *argv[])
     MainWindow mainWindow;
     mainWindow.show();
 
+    QGuiApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
+
     return app.exec();
 }
diff --git a/src/resources/haloray.qrc b/src/resources/haloray.qrc
index e56f2f1..19d54cf 100644
--- a/src/resources/haloray.qrc
+++ b/src/resources/haloray.qrc
@@ -1,5 +1,12 @@
-<!DOCTYPE RCC><RCC version="1.0">
-<qresource>
-    <file>haloray.ico</file>
-</qresource>
+<!DOCTYPE RCC>
+<RCC version="1.0">
+    <qresource prefix="/">
+        <file>haloray.ico</file>
+        <file>shaders/raytrace.glsl</file>
+    </qresource>
+    <qresource prefix="/icons">
+        <file alias="actions/24/list-add.svg">icons/custom-icons/actions/24/list-add.svg</file>
+        <file alias="actions/24/list-remove.svg">icons/custom-icons/actions/24/list-remove.svg</file>
+        <file alias="index.theme">icons/custom-icons/index.theme</file>
+    </qresource>
 </RCC>
diff --git a/src/resources/hexagon.svg b/src/resources/hexagon.svg
new file mode 100644
index 0000000..4caedad
--- /dev/null
+++ b/src/resources/hexagon.svg
@@ -0,0 +1,148 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Created with Inkscape (http://www.inkscape.org/) -->
+
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   version="1.1"
+   id="svg2"
+   width="256"
+   height="256"
+   viewBox="0 0 256 256"
+   sodipodi:docname="hexagon.svg"
+   inkscape:version="0.92.3 (2405546, 2018-03-11)">
+  <metadata
+     id="metadata8">
+    <rdf:RDF>
+      <cc:Work
+         rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
+        <dc:title></dc:title>
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <defs
+     id="defs6">
+    <filter
+       style="color-interpolation-filters:sRGB"
+       inkscape:label="Drop Shadow"
+       id="filter5080">
+      <feFlood
+         flood-opacity="0.235294"
+         flood-color="rgb(0,0,0)"
+         result="flood"
+         id="feFlood5070" />
+      <feComposite
+         in="flood"
+         in2="SourceGraphic"
+         operator="in"
+         result="composite1"
+         id="feComposite5072" />
+      <feGaussianBlur
+         in="composite1"
+         stdDeviation="1"
+         result="blur"
+         id="feGaussianBlur5074" />
+      <feOffset
+         dx="1"
+         dy="-1"
+         result="offset"
+         id="feOffset5076" />
+      <feComposite
+         in="SourceGraphic"
+         in2="offset"
+         operator="over"
+         result="composite2"
+         id="feComposite5078" />
+    </filter>
+  </defs>
+  <sodipodi:namedview
+     pagecolor="#ffffff"
+     bordercolor="#666666"
+     borderopacity="1"
+     objecttolerance="10"
+     gridtolerance="10"
+     guidetolerance="10"
+     inkscape:pageopacity="0"
+     inkscape:pageshadow="2"
+     inkscape:window-width="2560"
+     inkscape:window-height="1377"
+     id="namedview4"
+     showgrid="false"
+     inkscape:zoom="3.4435273"
+     inkscape:cx="115.05474"
+     inkscape:cy="163.65465"
+     inkscape:window-x="-8"
+     inkscape:window-y="-8"
+     inkscape:window-maximized="1"
+     inkscape:current-layer="svg2"
+     fit-margin-top="17.1475"
+     fit-margin-left="0"
+     fit-margin-right="0"
+     fit-margin-bottom="17.1475" />
+  <path
+     sodipodi:type="star"
+     style="display:inline;fill:#39a7d1;fill-opacity:1;fill-rule:nonzero;stroke:none;stroke-width:1.00657225;stroke-linecap:butt;stroke-linejoin:miter;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1;filter:url(#filter5080)"
+     id="path4522"
+     sodipodi:sides="6"
+     sodipodi:cx="41.236786"
+     sodipodi:cy="-40.97361"
+     sodipodi:r1="38.517841"
+     sodipodi:r2="33.357433"
+     sodipodi:arg1="1.0471976"
+     sodipodi:arg2="1.5707963"
+     inkscape:flatsided="true"
+     inkscape:rounded="0"
+     inkscape:randomized="0"
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+     transform="matrix(2.7692793,0,0,-2.7692793,13.803816,14.533884)"
+     inkscape:label="base" />
+  <path
+     style="fill:#39a7d1;fill-opacity:1;fill-rule:evenodd;stroke:none;stroke-width:2.76927948px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1"
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+     transform="scale(1,-1)"
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+     id="path4524"
+     style="fill:#45ccff;fill-opacity:1;fill-rule:nonzero;stroke:none;stroke-width:2.79805923;stroke-linecap:butt;stroke-linejoin:miter;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1"
+     sodipodi:type="star"
+     inkscape:label="middle" />
+  <path
+     style="fill:#3fbae8;fill-opacity:1;fill-rule:evenodd;stroke:none;stroke-width:2.76927948px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1"
+     d="M 99.487889,177.38567 74.666668,220.37729 21.333332,128.00126 h 49.642447 l 28.51211,49.38441"
+     id="path4536"
+     inkscape:connector-curvature="0"
+     inkscape:label="lowleft" />
+  <path
+     style="display:inline;fill:#6fd8ff;fill-opacity:1;fill-rule:evenodd;stroke:none;stroke-width:2.76927948px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1"
+     d="m 99.48788,78.616837 57.02422,-9e-6 24.82122,-42.991614 H 74.66666 l 24.82122,42.991623"
+     id="path4538"
+     inkscape:connector-curvature="0"
+     inkscape:label="top" />
+  <path
+     style="fill:#88deff;fill-opacity:1;fill-rule:evenodd;stroke:none;stroke-width:2.76927948px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1"
+     d="M 21.333332,128.00126 H 70.975779 L 99.48788,78.616837 74.66666,35.625214 Z"
+     id="path4540"
+     inkscape:connector-curvature="0"
+     inkscape:label="topleft" />
+</svg>
diff --git a/src/resources/hexagon_256px.png b/src/resources/hexagon_256px.png
deleted file mode 100644
index 2647abc..0000000
Binary files a/src/resources/hexagon_256px.png and /dev/null differ
diff --git a/src/resources/hexagon_appicon.psd b/src/resources/hexagon_appicon.psd
deleted file mode 100644
index 57a791a..0000000
Binary files a/src/resources/hexagon_appicon.psd and /dev/null differ
diff --git a/src/resources/icons/custom-icons/actions/24/list-add.svg b/src/resources/icons/custom-icons/actions/24/list-add.svg
new file mode 100644
index 0000000..fea171f
--- /dev/null
+++ b/src/resources/icons/custom-icons/actions/24/list-add.svg
@@ -0,0 +1,8 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24">
+ <defs>
+  <style id="current-color-scheme" type="text/css">
+   .ColorScheme-Text { color:#31363b; } .ColorScheme-Highlight { color:#3daee9; }
+  </style>
+ </defs>
+ <path style="fill:currentColor" class="ColorScheme-Text" d="M 7 3 L 7 7 L 3 7 L 3 9 L 7 9 L 7 13 L 9 13 L 9 9 L 13 9 L 13 7 L 9 7 L 9 3 L 7 3 z" transform="translate(4 4)"/>
+</svg>
diff --git a/src/resources/icons/custom-icons/actions/24/list-remove.svg b/src/resources/icons/custom-icons/actions/24/list-remove.svg
new file mode 100644
index 0000000..ee63a42
--- /dev/null
+++ b/src/resources/icons/custom-icons/actions/24/list-remove.svg
@@ -0,0 +1,8 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24">
+ <defs>
+  <style id="current-color-scheme" type="text/css">
+   .ColorScheme-Text { color:#31363b; } .ColorScheme-Highlight { color:#3daee9; }
+  </style>
+ </defs>
+ <path style="fill:currentColor" class="ColorScheme-Text" d="M 3 7 L 3 9 L 13 9 L 13 7 L 3 7 z" transform="translate(4 4)"/>
+</svg>
diff --git a/src/resources/icons/custom-icons/index.theme b/src/resources/icons/custom-icons/index.theme
new file mode 100644
index 0000000..194742f
--- /dev/null
+++ b/src/resources/icons/custom-icons/index.theme
@@ -0,0 +1,9 @@
+[Icon Theme]
+Name=HaloRayTheme
+Comment=Custom icons for HaloRay
+Directories=actions/24
+
+[actions/24]
+Size=24
+Context=Actions
+Type=Fixed
diff --git a/src/simulation/shaders/raytrace.glsl b/src/resources/shaders/raytrace.glsl
similarity index 94%
rename from src/simulation/shaders/raytrace.glsl
rename to src/resources/shaders/raytrace.glsl
index 941c4fc..e3e307b 100644
--- a/src/simulation/shaders/raytrace.glsl
+++ b/src/resources/shaders/raytrace.glsl
@@ -1,10 +1,3 @@
-#pragma once
-#include <string>
-
-namespace HaloSim
-{
-
-const std::string computeShaderSource = R""(
 #version 440 core
 
 #define DISTRIBUTION_UNIFORM 0
@@ -51,6 +44,8 @@ uniform struct camera_t
     int hideSubHorizon;
 } camera;
 
+uniform float multipleScatteringProbability;
+
 const float PI = 3.1415926535;
 
 struct intersection {
@@ -470,12 +465,28 @@ void main(void)
 
     if (length(resultRay) < 0.0001) return;
 
-    resultRay = -rotationMatrix * resultRay;
+    resultRay = rotationMatrix * resultRay;
+
+    if (multipleScatteringProbability != 0.0 && multipleScatteringProbability > rand())
+    {
+        // Rotation matrix to orient ray/crystal
+        rotationMatrix = getRotationMatrix();
+
+        /* The inverse rotation matrix must be applied because we are
+        rotating the incoming ray and not the crystal itself. */
+        rotatedRayDirection = resultRay * rotationMatrix;
+
+        resultRay = castRayThroughCrystal(rotatedRayDirection, wavelength);
+
+        if (length(resultRay) < 0.0001) return;
+
+        resultRay = rotationMatrix * resultRay;
+    }
 
     // Hide subhorizon rays
-    if (camera.hideSubHorizon == 1 && resultRay.y < 0.0) return;
+    if (camera.hideSubHorizon == 1 && resultRay.y > 0.0) return;
 
-    resultRay = getCameraOrientationMatrix() * resultRay;
+    resultRay = -getCameraOrientationMatrix() * resultRay;
 
     ivec2 resolution = imageSize(outputImage);
     float aspectRatio = float(resolution.y) / float(resolution.x);
@@ -515,5 +526,3 @@ void main(void)
     vec3 cieXYZ = daylightEstimate(wavelength) * vec3(xFit_1931(wavelength), yFit_1931(wavelength), zFit_1931(wavelength));
     storePixel(pixelCoordinates, cieXYZ);
 }
-)"";
-}
diff --git a/src/simulation/simulationEngine.cpp b/src/simulation/simulationEngine.cpp
index 383e2c2..2ee4a60 100644
--- a/src/simulation/simulationEngine.cpp
+++ b/src/simulation/simulationEngine.cpp
@@ -7,7 +7,6 @@
 #include "camera.h"
 #include "lightSource.h"
 #include "crystalPopulation.h"
-#include "shaders/raytrace.glsl"
 
 namespace HaloSim
 {
@@ -27,6 +26,7 @@ SimulationEngine::SimulationEngine(
       mCamera(Camera::createDefaultCamera()),
       mLight(LightSource::createDefaultLightSource()),
       mCameraLockedToLightSource(false),
+      mMultipleScatteringProbability(0.0),
       mCrystalRepository(crystalRepository)
 {
 }
@@ -136,6 +136,8 @@ void SimulationEngine::step()
         mSimulationShader->setUniformValue("camera.projection", mCamera.projection);
         mSimulationShader->setUniformValue("camera.hideSubHorizon", mCamera.hideSubHorizon ? 1 : 0);
 
+        mSimulationShader->setUniformValue("multipleScatteringProbability", mMultipleScatteringProbability);
+
         glDispatchCompute(numRays, 1, 1);
     }
 }
@@ -176,7 +178,7 @@ void SimulationEngine::initialize()
 void SimulationEngine::initializeShader()
 {
     mSimulationShader = std::make_unique<QOpenGLShaderProgram>();
-    mSimulationShader->addCacheableShaderFromSourceCode(QOpenGLShader::ShaderTypeBit::Compute, computeShaderSource.c_str());
+    mSimulationShader->addCacheableShaderFromSourceFile(QOpenGLShader::ShaderTypeBit::Compute, ":/shaders/raytrace.glsl");
     if (mSimulationShader->link() == false)
     {
         throw std::runtime_error(mSimulationShader->log().toUtf8());
@@ -214,4 +216,15 @@ void SimulationEngine::pointCameraToLightSource()
     mCamera.pitch = mLight.altitude;
 }
 
+void SimulationEngine::setMultipleScatteringProbability(double probability)
+{
+    clear();
+    mMultipleScatteringProbability = static_cast<float>(std::min(std::max(probability, 0.0), 1.0));
+}
+
+double SimulationEngine::getMultipleScatteringProbability() const
+{
+    return static_cast<double>(mMultipleScatteringProbability);
+}
+
 } // namespace HaloSim
diff --git a/src/simulation/simulationEngine.h b/src/simulation/simulationEngine.h
index aec1ab3..e921750 100644
--- a/src/simulation/simulationEngine.h
+++ b/src/simulation/simulationEngine.h
@@ -37,6 +37,9 @@ class SimulationEngine : protected QOpenGLFunctions_4_4_Core
 
     void lockCameraToLightSource(bool locked);
 
+    void setMultipleScatteringProbability(double);
+    double getMultipleScatteringProbability() const;
+
     const unsigned int getOutputTextureHandle() const;
 
     void resizeOutputTextureCallback(const unsigned int width, const unsigned int height);
@@ -62,6 +65,7 @@ class SimulationEngine : protected QOpenGLFunctions_4_4_Core
     unsigned int mRaysPerStep;
     unsigned int mIteration;
     bool mCameraLockedToLightSource;
+    float mMultipleScatteringProbability;
     std::shared_ptr<CrystalPopulationRepository> mCrystalRepository;
 };