({{1,0,0},{-1,1,0},{0,0,1}} dot {{1,0,0},{0,1,0},{2,0,1}} dot {{1,0,0},{0,1,0},{0,-4,1}}) dot ({{1,0,0},{0,1,0},{0,0,9}} dot {{1,0,0},{0,1,3},{0,0,1}} dot {{1,4,0},{0,1,0},{0,0,1}})