The child draws three bat shapes freehand or traces around a scrap paper template: one large (about 15 cm wingspan), one medium (about 10 cm) and one small (about 6 cm). Cut all three out carefully. A good bat silhouette has two curved wings, a slightly pointed head in the centre and two small ear triangles at the top.

Cut three lengths of string: 30 cm, 20 cm and 12 cm. Make a small hole near the centre of each bat's back using a sharp pencil tip pushed through the card, then thread the string through and tie a knot on the underside so it cannot pull through. Tie the large bat to the long string, the medium to the mid-length, and the small to the shortest.

An adult stretches the coat hanger into a rough diamond shape and ties each bat string along the bottom wire, spacing them evenly. Tie the loop end to something sturdy. Adjust the bat positions so the mobile hangs level. Store by sliding the bats off their strings and flattening them in a folder.