rndLst1 = Math.RandomList(xCount*yCount);
rndLst2 = List.Chop(rndLst1,yCount);
rndLst3 = List.TakeItems(rndLst2<1>,1..yCount);
rndLst4 = Math.Sum(rndLst3);
nrbCrv1 = NurbsCurve.ByControlPoints(List.Transpose
(Point.ByCoordinates((0..5..#xCount),rndLst4)),3);