This is awesome. Better execution than most web based tools I've seen to do similar. I'm fascinated by Escher's migrating tessellations of recognizable figures[0]. It would be nice to fork this and be able to draw a pair (or more) of figures then use a gradient to base a blending mask to sum them.
[0] https://mathstat.slu.edu/escher/index.php/Tessellations_by_R...