Question about nested lists!

[Alex]

The problem is that floor contains ten references to the same list, and
the command 'floor[5][5] = 1' sets the fifth element of this list to 1.
Then when you go to print out the elements in floor, you print out ten
copies of said list.

Really, you want to be making these sorts of multidimensional arrays
with Numerical Python.  Check it out at numpy.sourceforge.net

HTH
Alex.