changed tabs to spaces
Since we're not using these bindings, let's give them the

"we're not using this variable" variable name of _
add docstring, formatting

I won't change all the formatting in this project, but these
are examples of the preferred method (see
http://legacy.python.org/dev/peps/pep-0008/)
don't pass in unused size into display, var name

Since the inner loop is over spots, col -> spot
Make available a property so it looks like an attribute
Change incorrect, confusing comment (!)
question for author
x and y are being used incorrectly! x should be row, y should be column
(or they should just be switched)
question
factor out repeated code
more common recursion pattern

This makes much more sense to me - the old way was wrong I think
Was this a speed optimization? It doesn't make sense to me

(I see why it works, but I don't understand why it buys us much)