load_file(1, "fig8.ses")
secondorder=2
proc prun() {local i, j
	run()
	for j=0,1 for i=2,3 Graph[i].exec_menu("Keep Lines")
}

{
Graph[1].exec_menu("Keep Lines")
prun()
forall nseg=3  prun()
forall nseg=1  prun()
Graph[1].exec_menu("Keep Lines")
}