An adult (or older child) draws a large skull outline in white chalk or white pencil on the black card, roughly 20 cm tall. Include large round eye sockets, a triangular nose hole, and a wide jaw with rectangular teeth.

Tear the coloured paper into small squares and irregular pieces, roughly 1 cm across. Keep colours in separate piles.

Brush a small area of the skull interior with thinned PVA and press paper pieces onto it, leaving a tiny gap between each piece so the black card shows through as grout lines. Change colours freely; there is no rule here.

Leave the eye sockets and nose hole black, or fill them with a single colour for contrast. Fill the teeth area with white paper pieces if you have any, or leave the teeth as undecorated card.

Let the mosaic dry for ten minutes until the PVA is clear and the pieces are flat.