Flatten each tube. Cut each flattened tube into three shapes: a long rectangle for a rib or spine section (about 10 cm), and two small dumbbell shapes (cut by snipping a short section and pinching the ends to round them) for joints. You will end up with a pile of ribs and rounded knobs.

Paint all pieces with two coats of white chalk paint, letting the first coat dry for 20 minutes before adding the second. They should look chalky and opaque; cardboard drinks paint, so a second coat is always necessary.

Punch a hole at each end of every piece once the paint is fully dry.

Connect the pieces by pushing a split-pin fastener through the end hole of one piece and then through the end hole of the next, then spreading the pin's arms open on the back. Alternate long pieces and short dumbbell pieces to build up a skeleton-like chain. An adult should help insert and open the pins for younger makers.

Once you have a chain of about 40-50 pieces, run the black cord through the top hole of the first piece and tie a firm knot. Hang between two hooks.