Thanks for the facinating post. My mind had wondered onto this problem before but immediatly thought it unsurmountable in so far as a simple, tidy solution goes. Genius.

However, I can only see the second example working. The first example wouldn't be able to store enough values. e.g. in a simple 10 x 10 matrix there would be 100 values but your example would only store 20? I'm I missing something?

Appreciated

Jack, from the Jersey in the UK