xtrace	"poly-cylinder"
{
	procedure	pcyl	l,m,n, a,b,c, r,h, pn
	{
		nvar	pn=10;
		nvar	h=r;

		var		t1, x1,y1;
		var		t2, x2,y2;

		para	l,m,n;
		leverz	a,b,c;
		sim		r,r,h/2;
		boundary	sphere	0,0,0, sqrt (2)
		{
			var		i=0;
			while	lt (i - pn)
			{
				t1=2*PI*i/pn;
				t2=2*PI*(i + 1)/pn;
				x1=cos (t1);
				y1=sin (t1);
				x2=cos (t2);
				y2=sin (t2);
				poly	è„ñ 
				{
					pt	0,0,1;
					pt	x1,y1,1;
					pt	x2,y2,1;
				}
				poly	ë§ñ 
				{
					pt	x1,y1,1;
					pt	x1,y1,-1;
					pt	x2,y2,-1;
					pt	x2,y2,1;
				}
				poly	íÍñ 
				{
					pt	0,0,-1;
					pt	x1,y1,-1;
					pt	x2,y2,-1;
				}
				i=i + 1;
			}
		}
	}
}