Formula (in x and/or y):

Fill with Formula

Examples:
x > y
(x+y)%2 == 0
x%3 < 2 and y%3 < 2

Start/Stop random coloring

Start

Load image icon
(32 x 32 pixels) from URL:
Load

Timeout (ms):

Play

To use the 'Play' feature, save several different versions of your doodle.

Left Mouse Button:
drawing (click and drag)
Right Mouse Button:
deleting (click and drag)

Use the URL:
paper.silversky.ch/DYxvHLUx
to share with friends.

Simple as that.