I’m very disappointed with my purchase. The metal rods (31561) to hold the boards together are not long enough to reach the connector (31687).  Or board HX is too thick. Not sure which one. Also, a hole in board JA was drilled too deep and piece (20203) fell completely inside. Also found a large chunk taken out of piece ( ST). Now I have a very disappointed child that has been waiting for over a month for this junk. A good waste of $120. Never ordering from here again.