function exampleNurbsSurfacePlane(){
		
			var degree = 3
				, knots = [0, 0, 0, 0, 0.333, 0.666, 1, 1, 1, 1]
				, pts = [ 	[ [0, 0, -10], 	[10, 0, 0], 	[20, 0, 0], 	[30, 0, 0] , 	[40, 0, 0], [50, 0, 9] ],
							[ [0, -10, 0], 	[10, -10, 10], 	[20, -10, 10], 	[30, -10, 0] , [40, -10, 0], [50, -10, 0]	],
							[ [0, -20, 0], 	[10, -20, 10], 	[20, -20, 10], 	[30, -20, 0] , [40, -20, -2], [50, -20, 0] 	],
							[ [0, -30, 0], 	[10, -30, 0], 	[20, -30, 0], 	[30, -30, 0] , [40, -30, 0], [50, -30, 0]     ],  
							[ [0, -40, 0], 	[10, -40, 0], 	[20, -40, 0], 	[30, -40, 4] , [40, -40, -20], [50, -40, 0]     ],  
							[ [0, -50, 12], [10, -50, 0], 	[20, -50, 0], 	[30, -50, 0] , [50, -50, 0], [50, -50, 15]     ],     ]
				, wts = [ 	[ 1, 1, 1, 1, 1, 1],
							[ 1, 1, 1, 1, 1, 1],
							[ 1, 1, 1, 1, 1, 1],
							[ 1, 1, 1, 1, 1, 1],
							[ 1, 1, 1, 1, 1, 1],
							[ 1, 1, 1, 1, 1, 1] ];

			srf1 = new verb.NurbsSurface( degree, knots, degree, knots, pts, wts );

			var p5 = [50,-50,3]
				, p6 = [50,0,3]
				, p7 = [0,0,3]
				, p8 = [0,-50,3];

			srf2 = new verb.FourPointSurface( p5, p6, p7, p8 );

			udivs0 =60;
			vdivs0 =60;

			udivs1 = 2;
			vdivs1 = 2;

		}