Post's Correspondence Problem

Given the following 11 card types, can you arrange them so that the top and bottom strings are the same? You are permitted to use as many copies of each card type as you like. Restriction: your string must start with the letter S.

Post's Correspondence Problem

To check your answer, type in the string consisting of the 9 characters { S, X, 1, A, B, E, [, ] } below, and hit the Submit button.


Input string:



This puzzle was created by Andrew W. Appel for your enjoyment.