1. Close all the color A jump rings, and open 15 color B rings and 14 color C rings. Work a strip of European 4-in-1 with these rings.
2. Open another 15 color B rings and 14 color C rings.
3. Pick up the strip, and pinch the outer columns of As together. Look at the chain from one side, and you’ll see a football- or eye-shaped opening where two As from each column overlap. Notice that a B or a C from the center column of rings already goes through that opening. Slide an open B or C through the same opening, and close the ring.
4. Repeat step 3 along the length of the chain, following the established color pattern of Bs and Cs. This new row of rings pulls the flat chain into a box-shaped tube.