Zap and Thwap
Zap is a series of utilities, such as DOM drawing and an accurate, self-correcting game loop.
Thwap is a position-based physics engine, that allows for circle-circle and circle-line (constraint) collisions.
HSHG stands for Hierarchical Spacial Hash Grid, which is an implementation of a spatial hashing technique that is can be used on an infinitely large area. It does not require bounds to be set like other methods, such as quadtrees.