The Problem Pit

Lynne and Sam find themselves on a planet in the galaxy Trialviron. The galaxy's ruler, a mystic head named Duneedon, feigns an apology for whisking them away. He tells them to enter a chamber for retransport. Instead, Lynne and Sam find themselves in The Problem Pit. To escape, they have to solve a series of word puzzles. The last puzzle, which Lynne must solve herself, seeks five verbs that mean ""Move in circular orbit.""