I have this circuit : 

![enter image description here](https://i.stack.imgur.com/SDZhJ.jpg)

I'm trying to write down the logic of every output (W,X,Y,Z), to get a truth table out of it : 

```
W = NOT (A OR B) 
X = NOT A AND B 
Y = A AND NOT B
Z = A AND B 

```

But when compares to the source, my truth table is wrong, so I know that my logics are all wrong. 

I always start from the right to left everytime I want to understand a logic circuit, for example, in this case, output W is the output of an AND gate between two NOT parameters `W = NOT X AND NOT Y`, but where do "X" and "Y" in this case come from, obviously not A and B? Look at the logic circuit, I felt like I was lost in a maze! Any suggestions, or hints to help me to understand this kind of logic circuits easier is greatly appreciated!