Clue 1
Draw a diagram of the room.
There are actually three ways for the spider to get to the fly quickly:
Route A: Straight down theWEST wall, across the floor and straight up the EAST wall.
Route B: Down the WEST wall at an angle , across to the far wall, up the far wall and then onto the EAST wall.
Route C: Down the WEST wall at an angle, across to the far wall, up the far wall and then onto the ceiling and down the WEST wall to the fly.
A suggestion would be to open up the room into a "net" for each route.