Robots

Message	meaning
step	steps ahead
left	turns 90 degrees to left
right	turns 90 degrees to right
seewall	detects a wall immediately ahead
seenowall	detects empty square immediately ahead
face	faces direction (N=0,W=1,S=2,E=3)
mark	marks next square in given color (default: green)
say	displays a message
timescale	sets a time between steps

as a default, Robots are placed in an empty room.

examples: