[lbrandy]

Software is more like building a machine than either math or art. There've been attempts to make formally-provable programs (so it _is_ like math) but these are not in widespread use.

Go watch the Lockpicking Lawyer on youtube pick locks and trivially crack/open every lock ever made. This is, roughly, the best physical analog to what happens with computer programs and safety. The creators are trying but they have to be correct everywhere, from every angle, and the attacker only needs to find one weakness to break it.