a typical Jon errour
1/ should read > red to yellow so no > yellow & green are stationary
this can be done with the present move tool
yes yellow + green (&blue) if grouped could hinge on black ball
to red ,this is all fair with present move tool
now
to hinge the yellow to the red face would be a snap to instead of
angle , although maybe the problems I had with the odd tetrahedron angles
was when hindging with the protactor ,not nowing or not finding the snap-to.
this was all a year ago l’will have to redraw the tets ,possibly a hinge (by default) can utilize the one tool without loss of normal move fuctions,
plus hinging blue to green is an undefined or odd angle