1 2 3 4 5 6 7 +----+----+----+----+----+----+----+ | | 1| B | | | + + + +----+ + + + | | | 2| Ac | | | | | + + +----+ + + + + | | 3| ? | | | + + + + + + + + | | 4| Ca | | | +----+----+----+----+----+----+----+ robot B moves south 1 2 3 4 5 6 7 +----+----+----+----+----+----+----+ | | 1| | | | + + + +----+ + + + | | | 2| Ac | | | | | + + +----+ + + + + | | 3| ? | | | + + + + + + + + | | 4| B Ca | | | +----+----+----+----+----+----+----+ robot A moves west 1 2 3 4 5 6 7 +----+----+----+----+----+----+----+ | | 1| | | | + + + +----+ + + + | | | 2| A c | | | | | + + +----+ + + + + | | 3| ? | | | + + + + + + + + | | 4| B Ca | | | +----+----+----+----+----+----+----+ robot A moves south 1 2 3 4 5 6 7 +----+----+----+----+----+----+----+ | | 1| | | | + + + +----+ + + + | | | 2| c | | | | | + + +----+ + + + + | | 3| A ? | | | + + + + + + + + | | 4| B Ca | | | +----+----+----+----+----+----+----+ robot C moves north 1 2 3 4 5 6 7 +----+----+----+----+----+----+----+ | | 1| C | | | + + + +----+ + + + | | | 2| c | | | | | + + +----+ + + + + | | 3| A ? | | | + + + + + + + + | | 4| B a | | | +----+----+----+----+----+----+----+ robot C moves west 1 2 3 4 5 6 7 +----+----+----+----+----+----+----+ | | 1| C | | | + + + +----+ + + + | | | 2| c | | | | | + + +----+ + + + + | | 3| A ? | | | + + + + + + + + | | 4| B a | | | +----+----+----+----+----+----+----+ robot C moves south 1 2 3 4 5 6 7 +----+----+----+----+----+----+----+ | | 1| | | | + + + +----+ + + + | | | 2| C c | | | | | + + +----+ + + + + | | 3| A ? | | | + + + + + + + + | | 4| B a | | | +----+----+----+----+----+----+----+ robot A moves east 1 2 3 4 5 6 7 +----+----+----+----+----+----+----+ | | 1| | | | + + + +----+ + + + | | | 2| C c | | | | | + + +----+ + + + + | | 3| ? A | | | + + + + + + + + | | 4| B a | | | +----+----+----+----+----+----+----+ robot B moves north 1 2 3 4 5 6 7 +----+----+----+----+----+----+----+ | | 1| | | | + + + +----+ + + + | | | 2| C c | | | | | + + +----+ + + + + | | 3| B ? A | | | + + + + + + + + | | 4| a | | | +----+----+----+----+----+----+----+ robot B moves east 1 2 3 4 5 6 7 +----+----+----+----+----+----+----+ | | 1| | | | + + + +----+ + + + | | | 2| C c | | | | | + + +----+ + + + + | | 3| B? A | | | + + + + + + + + | | 4| a | | | +----+----+----+----+----+----+----+ robot A moves south 1 2 3 4 5 6 7 +----+----+----+----+----+----+----+ | | 1| | | | + + + +----+ + + + | | | 2| C c | | | | | + + +----+ + + + + | | 3| B? | | | + + + + + + + + | | 4| Aa | | | +----+----+----+----+----+----+----+ robot C moves east 1 2 3 4 5 6 7 +----+----+----+----+----+----+----+ | | 1| | | | + + + +----+ + + + | | | 2| Cc | | | | | + + +----+ + + + + | | 3| B? | | | + + + + + + + + | | 4| Aa | | | +----+----+----+----+----+----+----+ All goals are satisfied after 11 moves