“These And, Or, and Invert functions are logic blocks, and they can be connected in order to create other functions. For instance, the output of an Or block can be connected to an Invert block to create a Nor function: the Nor output will be a 1 when neither of its inputs is 1. In another example (using De Morgan’s theorem), we can make an And block by connecting two Invert blocks to the inputs of an Or block and connecting a third Invert block to the output (see Figure 6). These four work together to implement the And function, so the final output is 1 only when both the inputs are 1.”