Sorry, Monopoly. No offense, Barbie. Apologies, Mr. Potato Head.
Rubik's Cube (Getty Images)The world's best-selling toy isn't a game, a doll or a spud: it's a humble arrangement of 26 cubes, invented by a Hungarian architecture professor back in 1974.
In the 37 years since Erno Rubik first created his famous cube, it's sold over 350 million units, making the man himself a household name and propelling his cuboid conundrum into the history books. Although its three-dimensional nature makes it a tricky prospect for beginners, pros can solve it well under a minute. The world record? A mere 5.66 seconds.
Hard as that may be to believe, mathematicians have proved it's always possible to solve absolutely any cube arrangement, no matter how scrambled, in 20 moves or less. Deciding which 20 is the hard bit -- but we're here to help.
Squaring up to the Cube
It's natural to think of the cube as having six faces, each with nine cubes. But don't. Instead, think of it as 26 cublets, grouped into three categories: centers, edges, and corners.
Centers have one colored side, and are fixed together by the cube's internal spindle. They can move around but can't swap places, and there are six of them, one per face. Get in the habit of thinking of these as fixed points that indicate the proper color for each face.
The twelve edge cubes have two sides and can be found in the middle of a face. Corners, meanwhile, have three sides, and there are eight of them -- four on the top, four on the bottom.
Start at the beginning
There are lots of good methods for solving a Rubik's Cube, but some are easier than others. Most of the beginner-appropriate ones start the same way: solve the top face.
How? Pick a color (any color), and find the corresponding center cublet. Then move out the cublets that don't fit, and move in the ones that do. If you get one in the right place but with the wrong orientation, move it out and come back to it later. Once you're done, you'll have not only the top face one uniform color, but the top three cublets on each side face will also match; if not, you have an edge or corner in the wrong place.
Go "through the keyhole"
Having solved one face, you're probably pretty reluctant to undo your good work. But sometimes you need to step backwards to move forwards, and that's the principle behind this handy tip.
After solving the top face, the standard next step is to tackle the bottom, opposite face. One good way to do that is to deliberately move an edge piece out from the already finished top, making a "keyhole." As you maneuver pieces to solve the bottom face, you'll find that if you move them through the keyhole each time, you won't disturb the rest of the top. Once you're done with the bottom, it's a simple matter to move the keyhole piece back into place.
Develop your intuition
Stuck? That's not surprising. Once you've got the top and bottom faces down, matters get more difficult.
We suggest stopping there, rescrambling the cube, and starting over. Once you've gone from a complete cubescramble to a couple of finished sides, you'll have absorbed most of the principles and methods you'll need to finish up that elusive middle layer. But if you're still stuck, there are some great, step-by-step tutorials on the Web -- but be prepared to memorize some pretty complex move sequences. If you can hone your own intuition without detailed guides, you'll be a better solver.
Don't forget: lube your Cube
Are your twists just not as smooth as you think they should be? Maybe your cube is running dry. Twist the top face through 45 degrees, and use a flat-bladed screwdriver to gently pry out one of the edge pieces. Spray a small amount of silicon-based lubricant -- available from your local home improvement store -- into the gap. Replace the edge piece, and give your cube a good scrambling. You should find it much smoother, and your solving times should plummet.