Decoder
	Function: sets exactly one of n outputs to 1, based on unsigned binary value
	Input: ceil (lg n)
	Output: n bits (exactly one is 1, rest are 0)
	Example: 3-8 decoder
		Inputs: 3 bits representing UB number
		Output: 1 bit corresponding to the value of the UB number is set to 1
	Black box:
							z0
		x0					z1
							z2
		x1					z3
							z4
		x2					z5
							z6
							z7
	Truth table:
		x2	x1	x0	z7	z6	z5	z4	z3	z2	z1	z0
		0	0	0	0	0	0	0	0	0	0	1
		0	0	1	0	0	0	0	0	0	1	0
		0	1	0	0	0	0	0	0	1	0	0
		0	1	1	0	0	0	0	1	0	0	0
		1	0	0	0	0	0	1	0	0	0	0
		1	0	1	0	0	1	0	0	0	0	0
		1	1	0	0	1	0	0	0	0	0	0
		1	1	1	1	0	0	0	0	0	0	0
	Boolean expressions for each output:
		z0 = \x2\x1\x0				z4 = x2\x1\x0
		z1 = \x2\x1x0				z5 = x2\x1x0
		z2 = \x2x1\x0				z6 = x2x1\x0
		z3 = \x2x1x0				z7 = x2x1x0