There are a number of demonstrations of how a pen attached to an axel on a rotating wheel can draw a sine-wave and other waveforms, and I wondered about drawing shapes using the waveform as input instead. This is what this page does.
Imagine a device with a pen that can move up and down, and its vertical position is controlled by the incoming waveform. The drawing surface is attached to a circular disc spinning at a constant speed. These are the results.
waveform: Choose the shape of the incoming wave.
rotation speed: Speed at which wheel rotates.
rotations: A pattern will eventually repeat. Some repeat after just 1 rotation, others might take 4 or 12 or 16. If the pattern looks incomplete, try increasing the number of rotations.
wheel: Size of the spinning wheel relative to the wave shape (1 = wheel diameter matches range).
background / line: Background and line colors. You can enter HTML color names like black, blue, white, etc, or RGB colors beginning with a #, e.g. #ff6633.
width: Width of pen.
transp: Check the box to have the saved image with a transparent background.
Numbers can be entered as a value like 7.5 or 0.125, or a fraction like 1/4, 17/8, etc.
To update: press Enter, tab to the next field, or click the update button.
When you change the values, the URL in your browse also changes, so you can bookmark a particular pattern, or copy and paste the URL to share it.
Most browsers will allow you to right-click the shape and then save the image.