// a line, conducting two waving surfaces

command MyLine H V
{
	set V1 (100 - )
	set H (H -10)
        set V (V-10)
	set V1 (V1-10)

	pen 50
        line 0 H 50 V
	line 10 H 60 V
        line -10 H 40 V

	pen 50
        line 50 V1 100 H
        line 40 V1 90 H
	line 60 V1 110 H

	pen 100
        line H V H V1
        //line (H+1) V (H+1) V1
}

forever
{
        paper 0
	set H 
	set V 
        MyLine H V
}