Abstract: An assembly system for assembling panels. A CAP device is a generally round cylinder having on its outer surface four cam surfaces which have an expanding diameter in the circumferential direction. The CAP device can be inserted into a square tube with its large diameter part on the diagonal of the tube and then turned so as to engage the tube. A CLIP device has two tongues pivoting on the end of a partial cylindrical section so that a tube can be inserted into the partial cylindrical section and forces panels attached to the tongues over the back of the tube. A toothed projection on the partial cylindrical section engages a panel.