Can anyone inform me of a math problem that is easy going in one direction but difficult in the other, but using colors?
(Ignoring the one-one and onto concerns.)
YEllow maps to the color E: Evergreen.
ORange maps to the color R: Red.
Thus, if I give you an arbitrary color: BLack, you can easily tell me what it maps to (Yellow.)
Now, consider inverting this function.
What is Ember's pre-map? You will have to carefully consider every color, until you arrive at REd.
You would have to examine *all* colors in turn until you find one whose second letter is E.