Gallery
The Multifunction plotter tool shows a square wave approximated by a series of sine waves (Fourier Series).

The Butterfly Curve, plotted using the Parametric Function Plotter tool.
A wreath on a table, created using the Spirograph Tool

Discrete Fourier Transform Tool shows the DFT of a rectified sine wave
Simulation of a Binary Coded Decimal decoder circuit. This tool is built without any macros or even formulae entered directly in the cells, all functionality is achieved using Named Formulae and Conditional Formatting.
The Coupled ODE Solver tool works out the motion of a planet around a star. The Animated Charts Tool shows an animated version.
Fractal Image generated by the Mandelbrot Set Tool