Coily AI

I've been working a bit on making the snake, "Coily," chase Q*bert around the pyramid. I came up with an algorithm for deciding on which way the snake should jump, based on where he is and where Q*bert (his prey) is:

Deciding whether Q*bert is above or below the snake is pretty easy - I just compared row numbers. But picking between the left and right was more of a challenge. Eventually, I came up with an expression:

leftRightCriteria = coilyRow-preyRow - 2*(coilyRowPos-preyRowPos)

I found that if this "leftRightCriteria" was less than zero, then Q*bert was to the left of Coily; if it was greater than zero, then Q*bert was to the right of Coily; if it was zero, Q*bert was directly above or below Coily. So now I could apply this to the decision tree.