Tween.js by Soledad Penades is a fast and simple animation library that can interpolate "tween" values. I have created a binding for Tween.js for PythonJS, here, and integrated it with the GoogleBlockly THREE.js editor, the new animation blocks are efficiently driven by Tween.js and can animate translation and color. see my commit here.
Last night I was chatting with Erik de Bruijn (creator of The UltiMaker 3D printer) and he completely blew me away with his work he has been pioneering with GoogleBlockly and THREE.js to make a constructive solid geometry editor called "UltiShaper". Do not miss these youtubes he has posted!