Here's another one.
Purpose:
Was aiming for a manufactured texture shader that would pull in lines only at specific angles (like the fabric brush, but 30° increments). The empty square shape works to that effect, something like paper when layered. Works for some weird line art as is.
Parameters and behavior schemes:
Stylus is not required.
Windmill behavior scheme - Pumps length into modulo with B(0.5). Multiplies result by 24 (from 2*360/30). Then rounds by adding 0.5 and flooring (anything with frac 0.4 and below round down, 0.5 and up round up). Multiplies result by 30 to get closest multiple of 30°. There's probably an easier way to get a similar effect (with sin or something), but I was just goofing around.
Comments on use:
Turn the size up or down to get the different shapes shown in the preview.
Hope you like it.