th.abs(solver_1_eq_2[0] / solver_1_eq_2[1]);
    var q210 = Math.abs(solver_1_eq_2[1] / solver_1_eq_2[0]);    
    if(Math.abs(q101 - q210) < 0.1 || Math.abs(q110 - q201) < 0.1) {
        document.getElementById("reply_quest_8").innerHTML = "Sure! When lines are orthogonal, the solution always comes in one or two jumps. Plus one iteration to see if we're there.";
        document.getElementById("buttons_quest_8").style.display = 'none';
        quests[7] = 1;
    } else if(last_iterations <= 3){
        doc