Also could be considered Colors! 2D version, even if it doesn't have as many features as the actual Colors! app. Or, for long-ago fans of my Scratch projects, you could call it the long-awaited sequel to my "Fun with Paint" project. It is capable of drawing with multiple colors, erasing, and clearing, plus it sports an undo button. It can even redraw your entire picture once your finished, all with 1s1s!
(click+drag on variable) change color
(1) make sprite draw
(hold e) eraser
(u) undo button*
*undo button has some restrictions. It is incapable of restoring a cleared page or retaining a layer under an erased overlapping layer.