at 1 1 wood . at 1 1 wood . at 1 1 wood . at 1 1 wood . at 1 1 wood
#update: {
at X Y wood . + X 1 X' . + Y 1 Y' . + X'' 1 X . + Y'' 1 Y = at X' Y' fire . at X' Y'' fire . at X'' Y' fire . at X'' Y'' fire
at X Y fire . + X 1 X' = at' X' Y fire
at X Y fire . + Y 1 Y' = at' X Y' fire
() = #process
}
#process: {
at' X Y I = at X Y I
() = ()
}