This filter is probably the weirdest combination of complex inverse-maths and circle packing I’ve ever coded.
The rational function evaluated here is z= d/[(z-a)(z-b)(z-c)]. This kind of mapping on complex plane are conformal – that means the angles remain the same.
In the demo you can change the parameters a,b and c by dragging the blue grips on stage.
Where parameter d as a complex number is located on the unit circle |d|=1, is has the effect of rotating the output.
Click on above image to go to the demo, and have fun modifying the parameters. But hey, warning and please be careful: The results might get really artistic sometimes: