@property
    @_memo
    def _facenorm_cross_edge(self):
        ppts = self.ppts
        fnorms = self.face_normals
        fe12 = np.cross(fnorms, ppts[:,1] - ppts[:,0])
        fe23 = np.cross(fnorms, ppts[:,2] - ppts[:,1])
        fe31 = np.cross(fnorms, ppts[:,2] - ppts[:,0])
        return fe12, fe23, fe31
dataset/ETHPy150Open gallantlab/pycortex/cortex/polyutils.py/Surface._facenorm_cross_edge/swapped operands of `-`