“Falling sand games” were a beloved childhood curiosity, but when I set out to write my own in Javascript, performance got in the way of the scale and granularity I wanted. Could WebAssembly be the tool to build the sand simulation of my dreams, or is it still just for blog posts? I’ll share with you the history and beauty of falling sand games, what I learned building mine to leverage the power of modern browsers, and show you how WebAssembly can cooperate productively with the JS ecosystem to enable awesome web experiences.