code: def rotate_x(self, deg):
          
          rad = math.radians(deg)
          mat = numpy.array([
              [1, 0, 0, 0],
              [0, math.cos(rad), math.sin(rad), 0],
              [0, -math.sin(rad), math.cos(rad), 0],
              [0, 0, 0, 1]
          ])
          self.vectors = self.vectors.dot(mat)
          return self
docs: Rotate mesh around x-axis
  
          :param float deg: Rotation angle (degree)
          :return: