I wanted to see if a small balsa square stick could be strengthened by a tiny amount of basswood on the outsides - much like a spar.

I glued thin (think veneer-like) strips to a balsa stick, and then I reduced the thickness of the finished glue-up the next day using my surface sander. I only left about .010" of basswood per side, which you can see along with the dark glue bands in the second photo. (Not the large balsa grain in the middle)

Results - this is much stiffer than plain balsa, but adds little weight. I went ahead and failed it, and predictably it failed in compression. The failure was much more friendly than the twig-like snap! you get from a balsa stick. If forces were coming from one direction, the optimum structure would have one side of basswood twice as thick as the other.

You could make a really strong truss with this material. It would also be good for tail construction, being both stiff and light.

I used 1/32 basswood spars in the construction of my MicroBOT wing a couple of years ago. The polyhedral joint is quite similar to your test piece. at least on either side of the poly break. It has yet to fail, but then again I'm not trying fail it.
Very cool things you are trying.

Kind regards,

Stan Hinman