About cubic-bezier

I am currently learning about cubic-bezier(x1,y1,x2,y2) where maximum value for x and y can be 1. As x axis denotes time, I guess x2 will always have to be > x1. But what about y? Can y1>y2?

Both can be negative: theres no reason tme can’t be a negative number (though you can end up with very wierd results, and note some values aren’t mathematically possible so the whole thing will just be ignored if that’s the case). Easiest way to see is to play around with it: