Just take 100, 1'x1'x1' boxes and stack them into a square.

That will give you a visual of 100 cubic feet..

It will come out like a square L5' x W5' x H4' 25 boxes each layer stacked 4 layers high.

Or L4' x W4' x H5' 20 boxes each layer stacked 5 layers high.

That will give you a visual of 100 cubic feet..

It will come out like a square L5' x W5' x H4' 25 boxes each layer stacked 4 layers high.

Or L4' x W4' x H5' 20 boxes each layer stacked 5 layers high.