The flour chute, showing the rectangular side pieces
and tricky 3-D triangular spaces
The coffee seems to have done the trick, as we then worked out that we could fit rectangular pieces to the sloping part of the chute, and make simpler triangular pieces to join them to the upper and lower parts.
Ray's compound mitre saw managed to cut the first three triangular pieces, which have one edge at an angle other than 90 degrees to the flat surface as well as a 38 degree point angle. However, the fourth seemed to require a combination of angles and directions that the saw didn't want to accomodate. Finally, after many unsuccessful attempts, we made a jig to hold the wood at 45 degrees to the saw bed and finally glued the last piece in place.