the system in MHRD works with just one logical gate called NAND. I think, that many people, who learned to design logical gates, had done this with AND and OR. I will show in this chapter, that there is no difference between AND and OR on the one side and NAND on the other Side.

As an Example is the XOR gate:

a b | o
-----|---
0 0 | 0
0 1 | 1
1 0 | 1
1 1 | 0

If a and b are equal, than o is zero. If a and b are different than o is 1. In AND OR logic the solution is:

(a and not b) or (not a and b) = o

In NAND NAND logic the solution is:

(a nand not b) nand (not a nand b) = o

The inputs are the same, just the (and) or (and) combination is replaced by a (nand) nand (nand) combination, which makes things easier.