Scaling a vector

Scaling a vector only changes its norm, not its direction. E.g. given a vector one can modify the scale and watch the magnitude change:

• Increase scale
• Decrease scale
• Set scale = 0.5

A function to compute the norm looks like this (regular code fences are left untouched):

def norm(array):
    return sum(i**2 for i in array)**0.5

Math regions are never scanned for spans: and come through verbatim.