Homeworlds Puzzle: Mercury in Retrograde

Here’s another Binary Homeworlds puzzle. Like “Homeworlds Puzzle: The Prestige” (2020-06-16), this one was inspired by Raymond Smullyan’s The Chess Mysteries of Sherlock Holmes. I actually came up with this one before “The Prestige,” and originally posted it to BoardGameGeek back in early June.

For details of how I created the puzzle, and how I created the image (thanks to Sleafar on Puzzling StackExchange!), see the first post in this series.

According to Looney Labs’ website, the Pyramid Quartet standalone Homeworlds set goes on sale November 12. You can preorder it from Looney Labs!

The puzzle

Consider the following position in a game of Binary Homeworlds (using the Pyramid Quartet rules).

A graphical representation of the game state.

Lee (0,g2b1) y3-
Ray (1,r3b2) g1-r1y3g3
DS1 (g2) r2g3-r2y1
DS2 (y2) y3b1b3-
DS3 (b2) -r3y1y2g3
DS4 (y2) g1b1-b3
DS5 (b2) r1-
DS6 (g2) r1b3-
DS7 (g1) -r2r3y1

The stash is empty.

Lee has just moved. His move was not “pass.” What was it?

For the solution, see the discussion of this puzzle on BoardGameGeek.

Posted 2020-10-28