Awesome! That works!
Thanks for all your help.
I also found, in 2007, the extrude command, available in the
dashboard. There is a keyboard shortcut for it; hold down ctrl-alt
and select a face, then push or pull. It did not work on all the
rectangular solids in a previously built model, but it did work on a
fresh cube. Interestingly, it seems to create a new solid from the
extrusion, then group them. Selecting the original solid selects both
unless you hold down the alt key. Strange.