Design a good way to access levelflip without scripting

[Narre]

When #2042 is merged, flipping will (hopefully) be mostly polished and ready for use. With that in mind, I think it would be great to have a somewhat intuitive way to flip the level without using scripts, since not every level creator is comfortable with or even capable of (doesn't understand) scripting. Besides, it would be great to have a consistent way to flip levels that players could recognise and know what's about to happen (to avoid situations where one level designer uses buttons, one powerups, one random scripttriggers etc).

Edit: I have just realised the potion already flips the level. I've no idea when this was added or if it was always that way (if so, then I apologise for being stupid). Either way, I'm leaving this open since a bit of discussion can't hurt. Please feel free to laugh at me for not knowing and/or checking this before.

[Narre]

Suggestion: Make either levelflip() or Level.flip_vertically() (which one is up for discussion) the default behaviour of the red potion (edit: the latter already is, maybe discuss if it should be the former instead, or if there should be a unique graphical transition effect for flipping), and reserve the blue potion for a potential future mirroring (horizontal flipping) feature, as suggested in #863. This wouldn't affect existing levels using the potions for other uses since a powerup's script always has priority over its default behaviour.

[Narre]

Suggestion: Add a new sprite for a powerup specifically designed for level flipping, just like the suggestion above, except with a new sprite. Edit: pointless now that I realised the potion already does that, I'll leave this comment here just to discuss how the sprite should look.

[Rusty-Box]

I had an idea for updating the potion sprite by adding something like circling arrows to show what it does.

[Narre]

Suggestion: Add a completely new object specifically designed to trigger levelflip.

[Narre]

Downside: This would require some extra coding and I'm not sure whether a completely new object for this purpose isn't an unnecessary overkill.

[Narre]

Upside: This would allow for the implementation of some creative ideas when designing said object and could potentially lead to more creative ways of using the flipping feature.