MATLAB code to demonstrate [Fourier series][1] representation of periodic signals (as a sum of sinusoidal functions).

The animation shows an approximation of a square wave signal using the first 4-terms of its Fourier series.
(Change the parameters near the top of the code to manipulate the animations and explore other variations).

![animation1][6]
![animation2][7]

This was inspired by the following similar animations:
- [Fourier Series Animation using Circles][2]
- [Fourier series square wave circles animation][3]
- [Fourier series visualisation with d3.js][4]
- [Smooth motion of rotating circles][5]

[1]: http://en.wikipedia.org/wiki/Fourier_series
[2]: https://www.youtube.com/watch?v=LznjC4Lo7lE
[3]: http://en.wikipedia.org/wiki/File:Fourier_series_square_wave_circles_animation.gif
[4]: http://bl.ocks.org/jinroh/7524988
[5]: http://blog.matthen.com/post/42112703604/the-smooth-motion-of-rotating-circles-can-be-used
[6]: http://i.imgur.com/qW8rFrp.gif
[7]: http://i.imgur.com/tpVteqt.gif