Crowdfund.sol

 function vote() external inState(State.Funded) {
        if (now > successBy) {
            state = State.Failed;
            revert();
        }
        require(msg.sender != creator);
        require(contributions[msg.sender] > 0);
        require(votes[msg.sender] != currentStage);

        votes[msg.sender] = currentStage;
        agrees += 1;
        if (agrees >= totalContributions / 2) {
            agrees = 0;
            payStage();
            if (currentStage == stages) {
                state = State.Successful;
            } else {
                currentStage += 1;
            }
        }
    }

    function payStage() internal inState(State.Funded) returns (bool) {
        uint256 totalRaised = currentBalance;
        currentBalance = currentBalance.sub(balancePerStage);
        if (creator.send(balancePerStage)) {
            emit CreatorPaidStage(creator);
            return true;
        } else {
            currentBalance = totalRaised;
            state = State.Successful;
        }
        return false;
    }