Keep A Way Home
Keep one plain route that always finishes; range anywhere you can still get back to it.
Formerly Escape
Apollo 11’s free return: no burn, and the Moon slings you home.
Seen in Ron Gilbert and Lucasfilm Games, The Secret of Monkey Island, 1990
Try it on your work
Define one simple way the thing you're working on can be finished from any state: a default, a fallback, a plain version. Keep it working at all times. Then experiment anywhere, on one condition: you can always return to the plain version in one step. Stop when an experiment cannot; undo that step and mark the edge.
Keep a one-paragraph version of your project that is always true and always current. Write anything else, as wildly as you like, provided every page can be collapsed back to that paragraph. Stop when a page cannot.
Keep one table, one hour or one person that always holds tasks finishable in two minutes. Let every other part of the day range as far as it likes, as long as anyone is one move from that safe point. Stop whenever you choose.
How it has been used
Apollo 11 travelled towards the Moon on a free-return trajectory. Before lunar-orbit insertion, the path would loop the spacecraft around the Moon and bring it back to Earth without another engine firing, preserving a ready abort while the mission pursued its more ambitious aims. Exploration was permitted because a constrained route home remained available.
Where it leads
Grouped under Protect what still needs to work