221 CUBE PAGE
Information about 221 cubes, and how to solve them.
Here are some pictures of my (crude) custom made 221 cube. I made it with Legos, magnets, a metal ball, hot glue, tape, and colored paper.
To see videos of 221 cubes, click on one of the search results on this YouTube page:
http://www.youtube.com/results?search_query=%222x2x1%22+cube&search=Search
The 221 cube is a kind of Rubik's cube where there are 4 corners connected together to form a square. Each corner has colored stickers on its sides. Pairs of corners can be rotated 180°. The goal of the puzzle is to reach a solved state, where there is only one color of stickers on every face of the cube.
Consider that one corner of the 221 cube is "static", and does not move. One of the "dynamic" corners is able to occupy 3 different locations. The remaining 2 corners can be flipped 2 ways. By performing the calculation 3 * 2, or 3!, the number of permutations of the 221 cube can be found: 6.
This means that there are 6 possible combinations of corner positions... hence rendering the puzzle solvable by everyone. However, sufficient knowledge of the 221 cube can help sharpen your speed solving abilities.
I have made a simple flash 221 cube for all of you to use:
I present...
= THE ONLY METHOD =
Memorizing the solutions to the 6 permutations of the 221 cube is key to solving it quickly. First, I shall explain the notation which will be used in this explanation.
Relatively, the red corner pair of this cube is called the front, and the blue corner pair is the side. When the front of this cube is "turned", the two red corners are rotated 180°, and change positions. When the right is turned, the blue corner pair is rotated. The "girth" stickers are the blue, orange, green, and red stickers. The top stickers are yellow, and the bottoms stickers are yellow.
A B
These permutations are the easiest to solve. Turn the right of cube A, and the front of cube B.
C D
Cubes C and D are similar to A and B, except one side is turned differently. Look for mismatched girth stickers on each face. To solve cube C, turn front, then right. For cube D, turn right, then front.
E
Cube E is the most scrambled permutation. All of the girth stickers are mixed up, while the top and bottom stickers are together. Cube E can be solved with two sequences: Front, right, front, or right, front, right.
