openconstructor is an HTML5-based physics simulation for building and animating springy creations. It is an open-source reimplementation of the sodaplay browser game released by soda creative ltd in 2000.

https://github.com/OpenConstructor/OpenConstructor

This is not processing.js: "p5.js is a new interpretation, not an emulation or port, and it is in active development. An official editing environment is coming soon, as well as many more features!"

"Build New Games is an Open Web games developer site for in depth tutorials on Open Web game development. "