def invert(self):
        """ Multiplying a matrix by its inverse produces the identity matrix.
        """
        m = self.matrix
        d = m[0] * m[4] - m[1] * m[3]
        self.matrix = [
             m[4] / d, -m[1] / d, 0,
             -m[3] / d,  m[0] / d, 0,
             (m[3] * m[7] - m[4] * m[6]) / d,
             -(m[0] * m[7] - m[1] * m[6]) / d,
             1
        ]
def invert(self):
        """ Multiplying a matrix by its inverse produces the identity matrix.
        """
        m = self.matrix
        d = m[0] * m[4] - m[1] * m[3]
        self.matrix = [
             m[4] / d, -m[1] / d, 0,
             -m[3] / d,  m[0] / d, 0,
             (m[3] * m[7] - m[4] * m[6]) / d,
             -(m[0] * m[7] - m[1] * m[6]) / d,
             1
        ]
def invert ( self ) : m = self . matrix d = m [ 0 ] * m [ 4 ] - m [ 1 ] * m [ 3 ] self . matrix = [ m [ 4 ] / d , - m [ 1 ] / d , 0 , - m [ 3 ] / d , m [ 0 ] / d , 0 , ( m [ 3 ] * m [ 7 ] - m [ 4 ] * m [ 6 ] ) / d , - ( m [ 0 ] * m [ 7 ] - m [ 1 ] * m [ 6 ] ) / d , 1 ]
Multiplying a matrix by its inverse produces the identity matrix.
Multiplying a matrix by its inverse produces the identity matrix .