They're addictive, engrossing and maddening. Sliders have been around for well over a century, but how much do you know about these brain twisters?
Question 1 of 20
What is the first sliding puzzle commonly known as?
Question 2 of 20
What shape were the pieces of the original sliding puzzle, the 15 Puzzle?
Question 3 of 20
How many 15 Puzzle configurations are solvable?
Question 4 of 20
The 15 Puzzle became popular in which year?
Question 5 of 20
Who was the inventor of the 15 Puzzle?
Question 6 of 20
How can sliding puzzle pieces be moved?
Question 7 of 20
True or False: The simpler a sliding puzzle's design, the easier it is to solve.
Question 8 of 20
Why was the Pennant Puzzle of 1909 harder to solve than earlier sliding puzzles?
Question 9 of 20
True or False: Even computers have a hard time solving sliding puzzles.
Question 10 of 20
Ma's Puzzle, released in 1927, introduced what element into sliding puzzles?
Question 11 of 20
What is the key to solving sliding puzzles?
Question 12 of 20
The Japanese sliding puzzle Sokoban represents what kind of worker?
Question 13 of 20
What makes Sokoban especially difficult?
Question 14 of 20
What professional group has a history of sliding puzzle analysis?
Question 15 of 20
When mathematicians judge a puzzle PSPACE-complete, what does this mean?
Question 16 of 20
What claim is made for the computer-designed puzzle called Quzzle?
Question 17 of 20
Rubik's Cube, a relative of the sliding puzzle, created a sensation in which decade?
Question 18 of 20
How long did it take chess champion Bobby Fischer to solve Rubik's Cube?
Question 19 of 20
What is the world's record for solving Rubik's Cube?
Question 20 of 20