
You might have already seen the basic #logicgates before arriving at this article. #NOR gate has a special property amongst the gates. It allows users to design any logical Boolean expression using NOR gates alone if composed properly. This property is practiced to #NAND gates also.
A NOR is nothing but a gate that gives an inverted output of the OR gate. Let us take a short peek at the gate and its #truthtable.

Input A Input B Output Q
0 0 1
0 1 0
1 0 0
1 1 0
So how does this implementation actually work? Dive in right away.
NOT using NOR gate
This can be made by simply joining the two inputs of the NOR gate. Because a NOR gate is similar to an OR gate that leads to NOT gate, this immediately removes the "OR" part of the NOR gate, removing it from consideration and keeping just the NOT part.

The desired output of the NOT gate is Q = NOT( A ).

The implementation of the NOT gate using the NOR gate is A NOR A.
OR gate using NOR gate
The NOR gate is the inverted #circuit of an OR gate. So if we invert the NOR gate again, there it is, back to the OR gate. Check out the implementation for more clarity.

The expected output of the OR gate is Q = A OR B.

The implementation of the OR gate using NOR gates is { A NOR B } NOR { A NOR