Undo button

The undo button is a button that appears on the bottom left of the screen of any level.
== Description ==
It undoes an action, but it can undo the most recent action only once. Multiple undoes at once are impossible.
== Appearance ==
It appears to be an white anti-clockwise circle arrow surrounded by a white solid bordered circle. Both the icon and the circle become gray when no action is done or when the most recent action is already undone.
Category:Buttons