def angle(self, o, p1, p2):
        '''the angle between two points around origin (never used origin)

        eq= len(op1)**2 + len(op2)**2 - len(p1p2)**2 over
             / 2*len(op1)*len(op2) '''

        ##norm both points
        #p1 = self.normalize(p1)
        #p2 = self.normalize(p2)


        #lengths of both points from origin
        a = self.distance(o, p1)
        b = self.distance(o, p2)
        c = self.distance(p1, p2)

        print 'distance of a, b, c:', a, b, c


        #main equation
        cosC = (a ** 2 + b ** 2 - c ** 2) / (2 * a * b)
        print 'result of equation', cosC


        ##solve cos with var cosC
        #Ccos = math.cos(cosC)
        #print 'used equations result and cosd it', Ccos

        C = math.acos(cosC)
        print 'angle between the two points in relation to origin in rads', C

        degC = math.degrees(C)
        print 'C in degrees', degC
        return degC