When a wave with

amplitude moves through the spring toy, each coil is displaced farther to the right or left. As a result, the coils in a compression are squeezed together
.

This compression creates an area of higher pressure in the spring toy, as the coils are closer together and harder to compress further. As the wave continues to propagate through the spring toy, areas of compression and rarefaction alternate, causing the coils to compress and expand in a periodic fashion. This compression and expansion of the coils create the oscillatory motion characteristic of waves.