agreement.sol

contract C {
    address person1;
    address person2;
    
    bool person1Agreement = false;
    bool person2Agreement = false;
    
    function doWeAgree() constant returns (bool) {
        if (person1Agreement == true && person2Agreement == true)
            return true;
        else
            return false;
    }
    
    event agreement(bool, bool);
    
    modifier person1Mod {
        if (msg.sender != person1)
            throw;
        else
        _
    }
    
    modifier person2Mod {
        if (msg.sender != person2)
            throw;
        else
        _
    }
    
    function person1Agrees(bool agree) person1Mod {
        agreement(agree, person2Agreement);
    }
    
    function person2Agrees(bool agree) person2Mod {
        agreement(person1Agreement, agree);
    }
}