1. Input your string or use the default one:

or double click below slide button to generate a random string
(sliding the button to set up string length at first).

2. Click one letter (except 1st and last) as cycle-starting point to initialize the animation.

A). Now the hare caught up with the tortoise, their motion track are shown above;

B). Due to hare speed is twice tortise, so it is obvious to get this equation;

C). Rewrite it to full expression;

D). Eliminate the same tracks;

E). The horizontal line part and the circle part hold same length, so if we move tortise back to the start point, and slow down hare speed to 1. Then they will surely meet at the cycle start point!