Heist Of The DiamondDiscrete Mathematics Level 3
A thief, standing by the gate (down left corner), is going to steal a diamond from a guarded building with square corridors. The guard stands in the middle at the moment when the thief starts approaching the diamond. He can walk one unit per minute in the grid, and the guard also walks one unit per minute around the diamond along the red arrows. If the guard and the thief ever meet at the same coordinate, the guard will catch the thief. The thief will also be caught if he isn't back to the gate in 12 minutes.
How many different routes the thief can take to steal the diamond and then return to the gate without getting caught?