“Start counting her NUMBER OF FACES,” Kimmo Eriksson, Brush up
your Björner (2008). The time is right to annotate Kimmo
Eriksson’s memorable poem: 1. What are Chip firing games? Many
women will find it admirable if you tell her she makes your
CHIPS FIRABLE. Chip firing games are (solitary) games played on
graphs: each node of a directed graph contains a pile of chips.
A move consists of selecting a node with at least as many chips
as its outdegree, and sending one chip along each outgoing edge
to its neighbors. The remarkable property of these games is that
depending on the sizes of the piles, either the game continues
forever or it reaches a position where it cannot be played
further. In the latter case the final position, the number of
moves, and even the number of times each node fired do not
depend on the specific moves made along the game. Sheep firing
game (You may play the game by clicking on the picture;
disclaimer: we object to cruel treatment of animals) In the rest
of this post you can read about s