Implemented an Explosion data structure to leverage particle-system.
Modified particle-system and renamed it particle-system-exp.
Implemented a shell game (with loader, etc) to test the explosions
(recycling some keyboard functionality ... whack hack!).... any way ..

TODO:

Implement a fade (or minimize) effect on the explosions (all).

Implement explosion factory pattern to model all the explosions.
 --- look for the word factory among the comments.

Integrate explosions with collision detection.