pragma solidity 0.4.18;

contract ForceEther {

  bool youWin = false;

  // due to the throwing fallback function normally the contract cannot receive ether
  // if a contract selfdestructs with this contract as a target, the fallback function
  // does not get called => this.balance > 0 and thus the attacker wins
  function onlyNonZeroBalance() {
      require(this.balance != 0);
      youWin = true;
  }
  // throw if any ether is received
  function() payable {
    revert();
  }

}