This GT is based on the Gumowski-Mira chaotic attractor. A particular variant was called "Mythic Bird" due to its similarity to feathered wings.

The code to generate this is minimal:

X=0.01,Y=0 G=()=>MX+2(1-M)XX/(1+XX) for(I=N;I>0;I--) { plot(W/2+XSCALEX,H/2+YSCALEY) Z=X,X=Y+G()+A(1-BYY)*Y,Y=-Z+G() }

The co-efficients A, B and M decide the final shape.

In this version, M is selected randomly from a set of known values, and it generates wings, blobs, oil slicks, and various other organic shapes.