Ghost leg
Introduction
Ghost Leg (畫鬼腳) is a traditional Chinese game. It is often used to arrange or select things. It consists of some horizontal lines and vertical lines. Very often the number of vertical lines is the same as the number of people playing, and at the bottom lines there are certain items, e.g. things that will be given to the player. Unlike vertical lines, the number of horizontal lines can be zero or more. The horizontal lines can be drawn anywhere between two vertical lines, except that no horizontal lines crossing vertical ones. The general rule for playing this game is: first choose a line on the top, and follow this line downwards. If a horizontal line is encountered, follow the horizontal line to get to another vertical line and go downwards again. Repeat the above procedures until reaching the end of the vertical line. Then the player will be given the thing written at the bottom of the line.
An example of Ghost Leg: File:GhostLeg1.jpg
One player's route when playing Ghost Leg: File:GhostLeg2.jpg
If the elements written above the Ghost Leg are treated as a sequence, and after the Ghost Leg, these elements are of different order, and the sequence has been transformed to another permutation. Hence, Ghost Leg can be treated as a kind of permutating operator.
Definition
1. Track (軌)
Tracks are vertical lines in Ghost Leg.
2. Leg (腳)
Legs are horizontal lines in Ghost Leg.
Representation Method
1. Graphical Representation
The traditional way of representation involves horizontal and vertical lines.
2. Matrix Representation
As Ghost Leg is a permutation, it can be represented by matrices.
