%!
% an animated rotating yin-yang fractal
% rehmi and don, last touched Sat Jun 25 16:50:25 PDT 1988
% depends on don's animator.ps

/flipped false def
%/yincolor 0 0 .7 hsbcolor def
%/yangcolor 0 0 .1 hsbcolor def
%/bgcolor .5 .2 .7 hsbcolor def
/yincolor { 1 setgray } def
/yangcolor { 0 setgray } def
/bgcolor .5 def

%/step ($1) dup length 0 ne {cvi} {pop 10} ifelse def
%/depth ($2) dup length 0 ne {cvi} {pop 4} ifelse def
/harmonics
  [1 1 1 1 1]
?def
/depth harmonics length def

/rot 0 def

/yum {
        0 0 1 90 270 arc
        0 -.5 .5 270 90 arcn
        0 .5 .5 270 90 arc
        closepath
        fill
} def

/yinyang {
        gsave
        flipped {yangcolor} {yincolor} ifelse yum
        180 rotate
        flipped {yincolor} {yangcolor} ifelse yum
        grestore
} def

/recur {
    dup 1 ge {
        gsave
            harmonics length 1 index sub harmonics exch get
            rot mul rotate
            1 sub
            yinyang
            gsave
                .25 .25 scale
                0 3 translate
                recur
                0 -2 translate
                180 rotate
                recur
                0 2 translate
                recur
                0 2 translate
                180 rotate
                recur
            grestore
            1 add
        grestore
    } if
    pause
} def