Begin () {
trc = 1;
}
func OnLineHeader () {
ntrc = LH.NumTrc;
}
func OnTrace () {

	grx = Tr.RcPtXC;
	gry = Tr.RcPtYC;
	print (grx," ",gry,"\n");
	trc = trc + 1;
	if ( trc > ntrc ) trc = 1;
}