21	Horowitz, Marc		marc		6-3	3	y
	1. 38	Small bug in Clip():
		In 3D, points can have their LEFT and RIGHT bits turned
		on. Consider (-50, 0, -500).In your implementation this 
		is not possible, since you use else statements. Remove
		the else here and it will work.
	2. 30
	3. 30
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	   98