#835: Tree explain

[There is a binary Christmas tree, with each node a ball, and lights strung between parent and child nodes. Beneath it is a heap of presents - sorted with the largest on top, smaller presents connected to it with string. Next to the tree is Cueball and his parents, Hairbun and another Cueball.]

Cueball: It’s a Christmas tree with a heap of presents underneath!

Mother: …We’re not inviting you home next year.