Do you remember a year ago when I made a multitouch drawing thingie with d3js? https://healthyalgorithms.com/2014/12/12/introducing-smudge/
My 3 year old and I modded it, and may we now share “castle smudge” with you: http://bl.ocks.org/aflaxman/raw/26fc5aa0e14b01754b0f/
Healthy Algorithms 