Equilibrium, also known as "Equi-librium" is an interlocking puzzle in the shape of a sphere. Copyrighted in 1974 by Reiss Games, Inc., it consists of 6 closed arch pieces, 5 of which have pegs on their straight center. The two pegs block the other pieces from being shifted back or forth, only the sixth piece is different having only one peg and two notches. These notches are above and below where the peg would be located on the other pieces, allowing only this notched piece to be moved at first. When it is moved so the notch fits over another piece's peg, the two pegged piece can be moved. Once a two peg piece has been slid to the side, the notched piece can be moved to its second notch and lifted off. Once the notch piece is removed, all the others become loose and the puzzle usually crumbles into its remaining pieces. The challenge is to put it back together. Equilibrium was sold in a cardboard box, with a solution sheet enclosed.
- "It looks tranquilizing till you take it... apart, that is. But getting this well-designed sphere (and you) back together again won't be easy."
The secret in putting it back together involves not only holding the pieces in such a way that all three angles are supported so they can hold the others, but also knowing how to place the 'Key' or notched piece to lock it all together. A later colored version named "Sphere" was released by Net Block.
Saving the notched piece until last, set two pieces so they are facing away from each other, such as db, then place another between them at a 45 degree angle in a U shape. This will make the bottom of the sphere and serve as a platform for the other pieces. Rest the pieces on the middle finger to give them a firm base, with the thumb and first finger reaching through the U shaped piece so that the two db pieces can be held. Using the U shaped pieces as a table place two other pieces on either side of it, they will curve towards each other so that they hold the db pieces up, they will link together so that it won't be as wobbly. Then the notched piece should be slide down from the top, but it'll be stopped by two pegs. The notched piece will now give the side pieces a brace so they don't fall inward. The notched piece should be slid in so the first notch near the edge will meet the two pegs below it, push it onto the pegs, if done carefully this will cause one of the pegged pieces to sink down, as the first peg clears the center beam, move it more towards the center of the sphere, so the second notch is over the second peg. Slide the pegged piece back upward, now only the notched piece will be out of place. To lock the pegged piece into place push the notched piece to its center position.
- Rubik's Cube
- Alexander's Star
- Skewb Diamond
- Skewb Ultimate
- Burr puzzle
- Equilibrium's packaging