[Kludge]

Damn this is good but its clearly not for beginners lmao

Seems to me to be just an algorithm expressed more problematically than using algebra. If z =>1 then positive result, move back to line 1, if you take the actual coding out and just lay out the logic.

EDIT: Very well laid out tutorial for basic logic functions, in general, actually. You're essentially explaining wtf an algorithm is, long way round, but the best way.