I once had the surprising experience of having to help a postdoc with a PhD in mechanical engineering wrap his head around a block of Python code he was reading that looked like:

    x = f0()
    x = f1(x)

He was just mentally blocked on how all of these things could be true at the same time, and/or on how a variable could be used in setting its own value, since assigning a new value to x would change the value that had been passed to f1! His intuition was that this meant some kind of recursion-to-stability was at play.

All he needed was to be informed that this could be equivalently represented as

    x = f0()
    y = f1(x)

or

    x = f1(f0())