A concrete anti-de Sitter black hole with dynamical horizon having   toroidal cross-sections and its characteristics
  We propose a special solution of Einstein equations in the general Vaidya form representing a dynamical black hole having horizon cross-sections with toroidal topology. The concrete model enables us to study for the first time dynamical horizons with toroidal topology, its area law, and the question of matter flux inside the horizon, without using a cut-and-paste technology to construct the solution. 
Pouria Dadras, J. T. Firouzjaee and Reza Mansouri
gr-qc hep-th math-ph math.MP