Blog · 2026-09-27

How Poople Unlimited finds the shortest path (and why it prefers common words)

Every page on this site that says "shortest path" is backed by the same small piece of maths. Here is how it works, without the jargon.

Words as a map

Take every four-letter word in the dictionary and draw a line between any two that differ by one letter. LOOP connects to LOOK, LOOT, COOP, HOOP, LOOM and POOP. Now the puzzle "turn WORD into POOP" is the same as "find the shortest route on this map".

Breadth-first search

Start at POOP and ripple outwards: first everything one step away, then everything two steps away, and so on. The first time the ripple reaches your word, the number of steps it took is the minimum. This is called breadth-first search, and on a couple of thousand words it takes a few milliseconds in your browser, which is why the solver feels instant.

Why the answer prefers common words

Usually there are several shortest ladders. From MEAD you can reach POOP in six steps in dozens of ways. Showing a random one would often produce ladders full of obscure words. So among all shortest ladders we pick the one whose words are the most common in everyday English, using word-frequency data. That is why the solution you see reads like real words rather than Scrabble trivia. The original Poople does the same for its "yesterday" solution, and our answer pages follow that convention.

What "there were several ways" means

We also count how many distinct shortest ladders exist. One means the route was forced; a handful means there was some choice; dozens means the puzzle was forgiving. It's a nice hint about how hard a day was.