rectangles, or cavases, or ... ?

[Alan G Isaac]

I need to display many (e.e., 2000) small squares whose colors are udpated
each time a computation is complete.

One approach is to put rectangles on a single canvas.
Another approach is to put many canvases in a single frame.
Another approach is to create an image each iteration,
which is placed on a canvas.
Other?

Are there obvious considerations in the choice?
(Right now I do not need to interact with the squares,
but in the future I may need to.)

Thanks,
Alan Isaac