On the doubled tetrus
  The tetrus is a sort of big brother to the tripus, W.P. Thurston's example of a compact hyperbolic 3-manifold with totally geodesic boundary. We describe a sixfold cover of the double of the tetrus, itself a double, which fibers over the circle with fiber a closed surface of genus 19. We also record arithmeticity of the doubles and certain twisted doubles of the tripus and tetrus, and point out some consequences regarding families of covers. 
Jason DeBlois