Here are the rules for the 4th challenge:
- there are only 2 robots;
- the field has a black circle that must be detected by robots;
- the robot that leaves the interior of the circle loses the game;
- robots start at the yellow marks back to back.
This is the mat to use:
![](/files/collabspace/4/04/504/188504/images/b87a3d22f_opt.jpg)
This is an example of a combat between robots: