What is the difference between x=legs; and legs=x; if there's any?

Question

https://code.sololearn.com/c17bI3l4Rb27/?ref=app
Instead of legs=x; I wrote x=legs; but I noticed that the output in this case is 0.I am wondering why this happen.

Answer 1

The first one assigns legs value to x, the second one assigns x value to legs

Answer 2

Makes sense, thank you!