Sam Loyd's 'Back from the Klondike' maze
In 1898 Sam Loyd published a maze built to defeat the classic trick of solving mazes backward from the exit. Starting on the heart at the center of a numbered grid, you move exactly 3 squares in a straight line, in any of 8 compass directions, landing on a number. That number tells you how far to travel in a straight line, in any direction, for your next move - and so on. You win when a move carries you exactly one square past the edge. Why won't working backward from the exit crack it?
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Loyd built the grid so that many different squares carry the same number, meaning dozens of paths run backward from the exit and almost all of them dead-end deep inside the maze, so tracing back from the goal gives no real shortcut. Loyd's own published solution: southwest twice, northeast three times, southwest three times, then one 'bold strike' southeast to freedom. First printed in the New York Journal and Advertiser on 24 April 1898, Martin Gardner called Loyd's solution 'sneaky.'
— Sam Loyd, Sam Loyd's Cyclopedia of Puzzles — First published as a maze in the New York Journal and Advertiser, 24 April 1898
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