C.a.R. >
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Physics >
**Square Wheel**

Surprisingly, it is possible to ride with square wheels
without bumps, provided the street is somewhat special.

### Technical Information

A bit difficult to do. Since I wanted to show the
numerical features of C.a.R., I avoided any algebra or analysis. First, I
constructed an inverted hyperbolic cosine curve with a parameter cosh(0), and
computed its zeros -a and +a. Then the parameter was set, so that the
derivatives at the zeros were -1 and 1. Then a point x is animated from -a to a.
The tangents are computed numerically, and also the length of the curve to the
point x. This makes it possible to draw the wheel.