# Pyraminx

The Pyraminx is a 6 cm large mechanical puzzle in the shape of a regular tetrahedron, which is similar in principle and construction to the Rubik's Cube of Rubik Ernő. Therefore, the term magic pyramid is in use. Each of the four sides is composed of nine triangular segments, each of which all have the same color in the basic position on each side. With the internal rotation mechanism both the side surfaces and the corners may be brought by 120 ° rotations about its center back for cover. In this way, the moving parts to each other to change their position and can be moved to almost any point in the tetrahedron. The aim of the patience game is usually to bring the Pyraminx from a position in which the colors are mixed back into the parent basic position.

## History

The German puzzle inventor Uwe Meffert developed the Pyraminx in the late 1970s in the wake of the great success of the cube. A European patent was awarded Meffert in March 1981. Nevertheless, several versions of the puzzle, which today are partially released yet emerged. From which, although not all have the pyramid shape but they are based on the same mechanism and are basically the same. Likewise, there is a master Pyraminx, which has 16 triangles on each side. To distinguish it from the other hand Pyramorphix, although it looks just like a smaller version with four segments per page, but a different turning mechanism which is why it has in contrast to Pyraminx when dissolved changes its shape.

When Pyraminx the four corners and center parts form one unit, because the corners remain with every movement next to the midsection. While the corners are each still shot, what is the aesthetics of the puzzle, but does not change the difficulty. Indeed, there is also a variant of the Pyraminx, which has no cornerstones and thus resembles a truncated tetrahedron. Is known under the name Tetraminx.

## Combinations and difficulty

The Pyraminx consists of 14 moving parts, of which only ten are relevant to what are clearly less than the 20 of the Rubik's Cube. Specifically, these are: the four cornerstones, together with the corresponding four middle stones and six edge parts. Since the rotation of individual corners does not change the other parts, the corners are trivial and irrelevant to the solution.

Similar to the normal Rubik's Cube, the middle parts of the Pyraminx never change their position to each other, but they can change the orientation, ie, the three colors switch places. Excluding the corners other than eight, as it leads to a theoretical limit of 34 6! 26 positions. Due mechanism but only a quarter of them are accessible, leading to a number of 34 6! 24 = 933 120 results. Thus, the Pyraminx is much simpler than the Rubik's Cube, even as the Pocket Cube, which nevertheless still has more than 3.6 million positions. The Pyraminx was already completely algorithmically calculated: Each position requires a maximum of eleven trains to the basic position, not counting eventual turning of the corners. With inclusion of the four corners of the trivial, the number of possible positions increased by a factor of 34 to 75,582,720.

- Required rotations for directing the Pyraminx ( without rotation of the trivial corners)

## Mechanics

The mechanics of the Pyraminx compensates partly that of the 3 × 3 × 3 Rubik 's Cube.

So there is also a coordinate system here. The 4 center pieces (in the picture is one to see on the lower left edge ) are simply screwed on this. While in the coordinate system of the classic 3 × 3 × 3 version, the axes are perpendicular to each other, similar to the coordinate system of this toy in shape more like a tetrapod. The center pieces are octahedral, two opposing sides have a hole in the middle through which the respective corner piece or intersection of the axes can be fixed. 3 pages are visible in the assembled state and pasted with stickers and other 3 sides lie on the edge surfaces of.

The cornerstones are tetrahedral and are simply placed on the center pieces and therefore can not be rotated away from its central stone.

The curb stones are also tetrahedral. 2 pages are to be seen and pasted over, the remaining 2 show the inside of the Pyraminx. The common edge of the two surfaces that are not stuck, small plastic parts are attached. You are always, even when turning, in a recess of a center stone. Once the edges are rotated, these plastic parts run in the wells in the interior further. The edges are as it were hooked into the center stones. The depressions are always circular, exactly perpendicular to the opposite vertex of the tetrahedron when charging, so you can turn the pages you usually would in a Rubik 's Cube.