startshape fract

#define rule_fract(a) \
rule fract { \
	jopie { } \
	fract [ z .1 b .1 y 1 r      a s (1/sqrt(tan(a)^2 + 1)) ] \
	fract [ z .1 b .1 x 1 y 1 r (a-90) x (-1/sqrt(1/tan(a)^2 + 1)) s (1/sqrt(1/tan(a)^2 + 1))] \
} 

rule_fract(15)
rule_fract(20)
rule_fract(25)
rule_fract(30)
//rule_fract(35)
//rule_fract(40)
//rule_fract(45)
//rule_fract(50)
//rule_fract(55)
rule_fract(60)
rule_fract(65)
rule_fract(70)
rule_fract(75)

path jopie {
	LINEREL { x 1 y 0 }
	LINEREL { x 0 y 1 }
	LINEREL { x -1 y 0 }
	CLOSEPOLY { }
	//STROKE { width 0.08  }
}