From the website:
CAAT is a multi-instance director-based scene-graph manager. It is able to render using Canvas, WebGL and CSS with the same code base.
Features actors, containers, scene transitions, behaviors, interpolators, paths, custom affine transformation stack, timers, elements lifecycle, etc.
CAAT acts like a vector-based scene graph for Canvas (WebGL and DOM/CSS are also supported) much like Paper.js, but with a focus on actors exhibiting complex movements.