As you can see, we got difference between US and UK symbol.

In china, we use UK symbol system.

Here I just want to tell you two symbols that I think is very challenging.

1. 异或门（XOR gate），不同为1，相同为0

   $1 \oplus 0 = 1$

2. 同或门（XNOR gate），相同为1，不同为0

   $1 \odot 1 = 1$