“Hypertime in Haskell”, Gwern2012-01-10 (Haskell, time-travel, philosophy)⁠:

Implementing the Hypertime multiverse model of time travel in Haskell

• Sequences
• Infinite Lists
• List of Lists
• List of Shifting Lists
• List of Shifting Pairs of Lists
• List of Shifting Zippers
• Updating Zippers