Welcome to the Legends of Leiden Treasure Hunt by Leiden Ludens! This hunt is all about the world-renowned alumni of Leiden University. As you travel through town, you will encounter several QR codes like the one you just scanned. They each represent 1 of 7 puzzles related to Leiden legends. You can do the entire tour in one go, or do a puzzle every day – whichever way you prefer! (The QR codes aren’t going anywhere).

Puzzle #7

Einstein’s Café


This corner building has housed a café for at least a century. In the 1920’s, Einstein would come here with his friends and fellow university professors for discussions, food, and a game of chess. The famous physicist Hendrik Lorentz lived in the house across the street (Hooigracht 48), where he, Einstein, Ehrenfest and other contemporary geniuses spent much of their time developing theories and making discoveries.

Einstein is famous to this day for some of the developments he made at this very location, but he is also famous for something a little more playful. He developed a game of logic that, according to legend, he used to test the brightest of his students. Below, you find a slightly easier version of his original puzzle.

Three houses stand in a row; a yellow, a blue, and a red. The owners keep different pets and play different games. Using the hints below, riddle me this:

Who keeps cats?

  1. The blue house’s neighbour plays the Sims.
  2. The yellow house is in the centre.
  3. The Englishman plays Uno.
  4. The bird lives with The Sims player.
  5. The dog barks at the birds to its left.
  6. The German lives in the house on the right.
  7. The Risk player lives in the blue house.
  8. The Norwegian lives in the yellow house.


Type your answer behind the / in the url. Example: pastatplay.com/youranswer.

All typed answers must consist of alphabetical symbols only (no spaces, numbers or punctuation marks).