A big wooden door stands at the edge of the deck. Each friend's hop sends a little shock wave rolling along the floor, and the door creaks open a bit more each time. A shy purple puffball peeks out, steps out, and at last hops over to the friends. It rings the doorbell, and a whole family of colourful puffballs pops up in the doorway. Then all three friends hop together, the puffballs leap out, and they bounce along the deck in a happy row.