Basic HTML version of Foils prepared Sept 20 97
| We can also define $indexed2Dhash[$x][$y]{$z} which should be thought of as a hash labelled by two-dimensional indices |
| $hashof2Darray{$x}[$y][$z] should be thought of as a hash whose value is a 2D array |
| One can freely use such data structures as long as you use "full" number of indices |
| Issues that require understanding of implementation occur when you need to manipulate structure "as a whole" with less than full number of indices |