Sixth-turn flat three-manifold
= Sixth-turn flat three-manifold
The <mapping torus> of an order-six rotation of a hexagonal <flat torus> is a closed orientable <flat Riemannian manifold> with holonomy $C_6$. The screw rotation has angle $\pi/3$ and axial displacement $1/6$. Its first <Betti number> is one.