diff --git a/src/hexfft/__init__.py b/src/hexfft/__init__.py
index 0bf3edc..c948369 100644
--- a/src/hexfft/__init__.py
+++ b/src/hexfft/__init__.py
@@ -1,2 +1,2 @@
-from .hexfft import fftshift, ifftshift, fft, ifft, FFT
+from .hexfft import fft, ifft, FFT
 from .array import HexArray
diff --git a/src/hexfft/hexfft.py b/src/hexfft/hexfft.py
index 982a8ad..0be76a6 100644
--- a/src/hexfft/hexfft.py
+++ b/src/hexfft/hexfft.py
@@ -503,79 +503,6 @@ def mersereau_ifft(PX):
     return px.T / 4
 
 
-def fftshift(X):
-    N = X.shape[0]
-    n1, n2 = X.indices
-    m = hsupport(N, X.pattern).astype(bool)
-    shifted = HexArray(np.zeros_like(X), X.pattern)
-    if X.pattern == "oblique":
-        regI = (n1 < N // 2) & (n2 < N // 2)
-        regII = m & (n1 < n2) & (n2 >= N // 2)
-        regIII = m & (n2 <= n1) & (n1 >= N // 2)
-
-        _regI = (n1 >= N // 2) & (n2 >= N // 2)
-        _regII = m & (n1 >= n2) & (n2 < N // 2)
-        _regIII = m & (n2 > n1) & (n1 < N // 2)
-
-        shifted[_regI] = X[regI]
-        shifted[_regII] = X[regII]
-        shifted[_regIII] = X[regIII]
-
-    elif X.pattern == "offset":
-        m = m.T
-        n2 = n2 - N // 4
-        regI = m & (n1 < N // 2) & (n2 < N // 2)
-        regII = m & (n1 <= n2) & (n2 >= N // 2)
-        regIII = m & (n2 < n1) & (n1 >= N // 2)
-
-        _regI = m & (n1 >= N // 2) & (n2 >= N // 2)
-        _regII = m & (n1 > n2) & (n2 < N // 2)
-        _regIII = m & (n2 >= n1) & (n1 < N // 2)
-
-        shifted[_regI.T] = X[regI.T]
-        shifted[_regII.T] = X[regII.T]
-        shifted[_regIII.T] = X[regIII.T]
-
-    return shifted
-
-
-def ifftshift(X):
-    N = X.shape[0]
-    n1, n2 = X.indices
-    m = hsupport(N, X.pattern).astype(bool)
-    shifted = HexArray(np.zeros_like(X), X.pattern)
-
-    if X.pattern == "oblique":
-        _regI = (n1 < N // 2) & (n2 < N // 2)
-        _regII = m & (n1 < n2) & (n2 >= N // 2)
-        _regIII = m & (n2 <= n1) & (n1 >= N // 2)
-
-        regI = (n1 >= N // 2) & (n2 >= N // 2)
-        regII = m & (n1 >= n2) & (n2 < N // 2)
-        regIII = m & (n2 > n1) & (n1 < N // 2)
-
-        shifted[_regI] = X[regI]
-        shifted[_regII] = X[regII]
-        shifted[_regIII] = X[regIII]
-
-    elif X.pattern == "offset":
-        m = m.T
-        n2 = n2 - N // 4
-        regI = m & (n1 < N // 2) & (n2 < N // 2)
-        regII = m & (n1 <= n2) & (n2 >= N // 2)
-        regIII = m & (n2 < n1) & (n1 >= N // 2)
-
-        _regI = m & (n1 >= N // 2) & (n2 >= N // 2)
-        _regII = m & (n1 > n2) & (n2 < N // 2)
-        _regIII = m & (n2 >= n1) & (n1 < N // 2)
-
-        shifted[regI.T] = X[_regI.T]
-        shifted[regII.T] = X[_regII.T]
-        shifted[regIII.T] = X[_regIII.T]
-
-    return shifted
-
-
 def _hexdft_pgram(px):
     """"""
     dtype = px.dtype
diff --git a/src/hexfft/utils.py b/src/hexfft/utils.py
index 11ae8d0..da46ed0 100644
--- a/src/hexfft/utils.py
+++ b/src/hexfft/utils.py
@@ -111,14 +111,88 @@ def pgram_to_hex(p, N, pattern="oblique"):
     return HexArray(h, pattern)
 
 
-def filter_shift(x):
+def fftshift(X):
+    N = X.shape[0]
+    n1, n2 = X.indices
+    m = hsupport(N, X.pattern).astype(bool)
+    shifted = HexArray(np.zeros_like(X), X.pattern)
+    if X.pattern == "oblique":
+        regI = (n1 < N // 2) & (n2 < N // 2)
+        regII = m & (n1 < n2) & (n2 >= N // 2)
+        regIII = m & (n2 <= n1) & (n1 >= N // 2)
+
+        _regI = (n1 >= N // 2) & (n2 >= N // 2)
+        _regII = m & (n1 >= n2) & (n2 < N // 2)
+        _regIII = m & (n2 > n1) & (n1 < N // 2)
+
+        shifted[_regI] = X[regI]
+        shifted[_regII] = X[regII]
+        shifted[_regIII] = X[regIII]
+
+    elif X.pattern == "offset":
+        m = m.T
+        n2 = n2 - N // 4
+        regI = m & (n1 < N // 2) & (n2 < N // 2)
+        regII = m & (n1 <= n2) & (n2 >= N // 2)
+        regIII = m & (n2 < n1) & (n1 >= N // 2)
+
+        _regI = m & (n1 >= N // 2) & (n2 >= N // 2)
+        _regII = m & (n1 > n2) & (n2 < N // 2)
+        _regIII = m & (n2 >= n1) & (n1 < N // 2)
+
+        shifted[_regI.T] = X[regI.T]
+        shifted[_regII.T] = X[regII.T]
+        shifted[_regIII.T] = X[regIII.T]
+
+    return shifted
+
+
+def ifftshift(X):
+    N = X.shape[0]
+    n1, n2 = X.indices
+    m = hsupport(N, X.pattern).astype(bool)
+    shifted = HexArray(np.zeros_like(X), X.pattern)
+
+    if X.pattern == "oblique":
+        _regI = (n1 < N // 2) & (n2 < N // 2)
+        _regII = m & (n1 < n2) & (n2 >= N // 2)
+        _regIII = m & (n2 <= n1) & (n1 >= N // 2)
+
+        regI = (n1 >= N // 2) & (n2 >= N // 2)
+        regII = m & (n1 >= n2) & (n2 < N // 2)
+        regIII = m & (n2 > n1) & (n1 < N // 2)
+
+        shifted[_regI] = X[regI]
+        shifted[_regII] = X[regII]
+        shifted[_regIII] = X[regIII]
+
+    elif X.pattern == "offset":
+        m = m.T
+        n2 = n2 - N // 4
+        regI = m & (n1 < N // 2) & (n2 < N // 2)
+        regII = m & (n1 <= n2) & (n2 >= N // 2)
+        regIII = m & (n2 < n1) & (n1 >= N // 2)
+
+        _regI = m & (n1 >= N // 2) & (n2 >= N // 2)
+        _regII = m & (n1 > n2) & (n2 < N // 2)
+        _regIII = m & (n2 >= n1) & (n1 < N // 2)
+
+        shifted[regI.T] = X[_regI.T]
+        shifted[regII.T] = X[_regII.T]
+        shifted[regIII.T] = X[_regIII.T]
+
+    return shifted
+
+
+def filter_shift(x, periodicity="rect"):
     """
-    Shift the quadrants of a HexArray to move the origin to/from
+    Shift the quadrants/thirds of a HexArray to move the origin to/from
     the center of the grid. Useful if a filter kernel is easier to define
     the origin at the center of the grid.
     """
-    if not isinstance(x, HexArray):
-        x = HexArray(x)
+
+    if periodicity == "hex":
+        return ifftshift(x)
 
     N1, N2 = x.shape
     out = HexArray(np.zeros_like(x), x.pattern)
diff --git a/tests/test_api.py b/tests/test_api.py
index b707741..4b60c80 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -1,4 +1,4 @@
-from hexfft import HexArray, fft, ifft, FFT, fftshift, ifftshift
+from hexfft import HexArray, fft, ifft, FFT
 from hexfft.array import rect_shift, rect_unshift
 import numpy as np
 import pytest
diff --git a/tests/test_hexfft.py b/tests/test_hexfft.py
index 10fdb43..c2fe878 100644
--- a/tests/test_hexfft.py
+++ b/tests/test_hexfft.py
@@ -1,4 +1,4 @@
-from hexfft import fftshift, ifftshift, HexArray
+from hexfft import fft, ifft, FFT, HexArray
 from hexfft.hexfft import (
     _hexdft_pgram,
     _hexidft_pgram,
@@ -8,15 +8,14 @@
     mersereau_ifft,
     rect_fft,
     rect_ifft,
-    FFT,
-    fft,
-    ifft,
 )
 from hexfft.utils import (
     hsupport,
     pgram_to_hex,
     nice_test_function,
     hex_to_pgram,
+    fftshift,
+    ifftshift,
 )
 from hexfft.array import rect_shift, rect_unshift
 from hexfft.reference import (