startshape start rule start { fern{ r 90 } // fern{ r -90 y 1 } } rule fern { spike{} fern{ r +60 s (1/3) x 1 } fern{ r -60 s (1/3) x 1 } // uncomment for color version fern{ r 5 s 0.9 x 1 b .1 hue 10 sat 1 } // uncomment for b/w version //fern{ r 5 s 0.9 x 1 } } path spike{ MOVETO{ x 0 y -0.1 } LINETO{ x 1.1 y -0.1} LINETO{ x 1.1 y +0.1} LINETO{ x 0 y +0.1 } CLOSEPOLY{} }