Hello there!
Just a little experiment:
shader MBox(
int size = 1,
output closure color CL = holdout()
){
float Prender(point P){
for(int i = 0; i <= size; i++) {
P *= P+sin((i*0.03)*sin(P*0.3*length(P*0.02)*0.0251))*0.033;
if(length(P) <= 0.2 && length(P) > 0.18 ) {
CL = emission()*color(noise (P / 0.02),noise (P / 0.01),noise (P / 0.03))*1.3;
}
}
return 0.0;
}
Prender(P);
return;
}
Desired effect:
Cheers!