Solution to: Sneaking Spider

The shortest path between two points in a plane is a straight line. Since the spider moves via the sides of the room only, we can "unfold" the room to make it a plane, as follows:

	front
left	ceiling
	back
	floor	right

Point A indicates the spider, which is positioned 25 centimeters below the ceiling in the middle of one of the short walls. Point C indicates the sleeping fly, which is located 25 centimeters above the floor in the middle of the opposite wall.

The shortest path between the spider and the fly is the straight line AC. Since AB has a length of 1.5 + 3 + 1.5 = 6 meters and BC has a length of 0.25 + 7.5 + 0.25 = 8 meters, AC has a length of 10 meters.

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