law: Transfer of Property Act, 1882
  31. Condition that transfer shall cease to have effect in
  
  case specified uncertain event happens or does not happen
  Subject to the provisions of section 12, on a transfer of
  
  property an interest therein may be created with the condition superadded that
  
  it shall cease to exist in case a specified uncertain event shall happen, or in
  
  case a specified uncertain event shall not happen.
  Illustrations
  (a) A transfers a farm to B for his life, with a proviso that,
  
  in case B cuts down a certain wood, the transfer shall cease to have any
  
  effect. B cuts down the wood. He loses his life-interest in the farm.
  (b) A transfers a farm to B, provided that, if B shall not go to
  
  England within three years after the date of the transfer, his interest in the
  
  farm shall cease. B does not go to England within the term prescribed. His
  
  interest in the farm ceases.