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Pentalpha
Encyclopedia
Pentalpha is a puzzle
where the goal is to place nine stones on the ten intersections
of a pentagram
. The following rules need to be obeyed when placing the stones:
The solution to Pentalpha can be found for any starting point using the following algorithm
:
Puzzle
A puzzle is a problem or enigma that tests the ingenuity of the solver. In a basic puzzle, one is intended to put together pieces in a logical way in order to come up with the desired solution...
where the goal is to place nine stones on the ten intersections
Line-line intersection
In Euclidean geometry, the intersection of a line and a line can be the empty set,a point, ora line. Distinguishing these cases, and finding the intersection point have use, for example, in computer graphics, motion planning, and collision detection....
of a pentagram
Pentagram
A pentagram is the shape of a five-pointed star drawn with five straight strokes...
. The following rules need to be obeyed when placing the stones:
- The stone has to visit two other points before reaching its final point.
- These three points have to be next to each other.
- The points have to be in a straight line.
- The first and third (final) points are not allowed to be occupied, the second point is.
Solution
![](http://image.absoluteastronomy.com/images/encyclopediaimages/p/pe/pentalpha.gif)
Algorithm
In mathematics and computer science, an algorithm is an effective method expressed as a finite list of well-defined instructions for calculating a function. Algorithms are used for calculation, data processing, and automated reasoning...
:
- Choose a node X.
- Travel two nodes in a straight line to node Y.
- From node Y, place a stone at node X.
- Let node Y be the new node X.
- Repeat step 2-4 until the puzzle is solved.
- Congratulations for completing it.