code: private void fillM( Point2D_F64 x1 , Point2D_F64 x2 , Point2D_F64 x3 ) {
  		M.data[0] = x1.x; M.data[1] = x1.y; M.data[2] = 1;
  		M.data[3] = x2.x; M.data[4] = x2.y; M.data[5] = 1;
  		M.data[6] = x3.x; M.data[7] = x3.y; M.data[8] = 1;
  	}
docs: Fill rows of M with observations from image 1