There are a whole range of different classroom activities on the

Explore section of the Geometry Expressions website.

Here are some of our favorites..

**String art** is a very nice lesson sequence examining the properties of parabolic curves found in simple string art designs.

**Light caustics** looks at the curves formed by light reflected in a cylinder (such as a coffee cup).

**From inductive reasoning to proof by induction** is an easy introduction to Geometry Expressions in an activity which uses inductive reasoning and introduces inductive proof.

**Sketching an ellipse at the beach** uses sticks and string on a beach to draw an ellipse, and some other surprising curves.

**Trammels**
The trammel of Archimedes draws ellipses with given semi-major
axes. This activity maps between this representation and the
pin/string representation.

**Where to take a rugby kick** solves an old standard calculus problem using Geometry Expressions.