Berb, that purly puts multiple arrays in series and probably uses the same formla I provided. In our case thats 4 arrays in series.
SlayerII, although hashtables do seem to act like 2D arrays and can be used as them, it is still more efficent to use a proper array in a 2D mode like that I provided. Hashtable lookup is great for wide range data while keeping lookup speeds near constant but can never beat a simple array.