I feel like the checkbox grid should have been locked to a certain width. I can see people attempting to draw things, but they're skewed on my screen.
(I made the site) this was on purpose! I figured there have been enough collaborative internet drawing experiences (with a locked canvas that was easy to draw on) that it'd be interesting to try something a little different and see what emerged. That said, it might be a dumb idea! But I wanted to try it.
If one uncheck and check again should claim it as checked