Peg potting mechanism

[w_bwr]

i 'm designing a line follower robot. which has 30*30 cm chasis and 4 wheeled with differential drive.
there are peg stands (see figure) at the corners of the arena. what should be mechanism for peg potting.
it can have maximum of two peg placement outlets.
The robot can place a maximum of three pegs in a single stand. The robot can not place more than one peg in the similar numbered pigeon-hole even on a different stand.
suggest a peg potting mechanism...

[corrado33]

Could you make 4 3x3 arrays.  Then you could number the pegs.  Put number one and two in the first and second slot in the first array (first peg stand), then place 3 and 4 in the second peg stand (in the third and forth positions) etc.

[w_bwr]

NO, the maximum number of outlets is 2.

this video 'll help to have better understanding.
Wall-E Robot(NERC 2009)


the robot has to pot 8 pegs on different holes even in the different stand. this robot pots 6 pegs differently but 7 or 8 hole cannot be different!
look at pic no 2(1.jpg) in my last post