> Could you define for me a 3 by 3 matrix? 
> What is the web reference for NArray?
> Thank you very much.
> Bob Ashworth

a=[[1,2,3],[4,5,6],[7,8,9]]

Here's an example output from IRB:

irb(main):004:0> a=[[1,2,3],[4,5,6],[7,8,9]]
[[1, 2, 3], [4, 5, 6], [7, 8, 9]]
irb(main):005:0> a
[[1, 2, 3], [4, 5, 6], [7, 8, 9]]
irb(main):006:0> a[2][2]
9

Have fun!

Michael