not so much a game, watch the things eat the 'food' and flock together. Mostly I was just playing with flocking . As each white block runs over a smaller coloured block they become that colour, and the blocks of the same colour will flock together.  Each block has a random chance of producing a clone of itself so over time the numbers grow. 

Clicking in the scene will direct all the blocks to that point until they reach it, where they will continue moving around at random.