After accidentally casting himself adrift in space, an astronaut's mind wanders over varied paths.
"According to his calculations, Barington had now been adrift in space for three months. This figure was based on his sleep schedule, which, although inexact, was his only possible point of reference. Whenever he determined that a day had passed, he reached up into his helmet and marked the inside of his visor with a tally, using a wax pencil he had found in his suit’s utility compartment. After the accumulation of seven tallies, he erased them with his thumb and drew a W for Week."