thanks for those. that's a snug looking frame.

tetrahedon sounds like a lot of sides...

i think there's going to be a turnbuckle connecting the long diagonal, and pulling against the rafters. the funny angles were making life look complicated. the idea of scribing down a beam across the tops of two beams at different heights only looks doable if they're rounded on the top, and these beams are square.

what would be even nicer is some spider web thread - organic and nearly invisible - to pull the corners together. any materials engineers out there? we love ya