text: // global constants
  const clueHoldTime = 1000; //how long to hold each clue's light/sound
  const cluePauseTime = 333; //how long to pause in between clues
  const nextClueWaitTime = 1000; //how long to wait before starting playback of the clue sequence
  
  //Global Variables
  var pattern = [];
  var progress = 0;
  var gamePlaying = false;
  var tonePlaying = false;
  var volume = 0.5; //must be between 0.0 and 1.0
  var guessCounter = 0;
  var time;
  var timer;
  
  // Init Sound Synthesizer
  var context = new AudioContext();
  var o = context.createOscillator();
  var g = context.createGain();
  
  function randomPattern() {
    for (let i = 0; i < 8; i++) {
      pattern[i] = Math.floor(Math.random() * 6 + 1);
    }
  }
  
  function myTimer() {
    if (time == -1) {
      clearInterval(timer);
      loseGame();
      return;
    }
  
    if (time < 10) {
      document.getElementById("timer").innerHTML = "Time Remaining: 0:0" + time;
    } else if (time >= 70) {
      document.getElementById("timer").innerHTML =
        "Time Remaining: 1:" + (time - 60);
    } else if (time >= 60) {
      document.getElementById("timer").innerHTML =
        "Time Remaining: 1:0" + (time - 60);
    } else {
      document.getElementById("timer").innerHTML = "Time Remaining: 0:" + time;
    }
  
    time--;
  }
  
  function startGame() {
    //initialize game variables
    progress = 0;
    gamePlaying = true;
    randomPattern();
    time = 90;
    timer = setInterval(myTimer, 1000);
  
    // swap the Start and Stop buttons
    document.getElementById("startBtn").classList.add("hidden");
    document.getElementById("stopBtn").classList.remove("hidden");
    document.getElementById("timer").classList.remove("hidden");
    playClueSequence();
  }
  
  function stopGame() {
    gamePlaying = false;
    clearInterval(timer);
  
    document.getElementById("startBtn").classList.remove("hidden");
    document.getElementById("stopBtn").classList.add("hidden");
    document.getElementById("timer").classList.add("hidden");
  }
  
  // Sound Synthesis Functions
  const freqMap = {
    1: 261.5,
    2: 329.5,
    3: 392.1,
    4: 466.3,
    5: 510.3,
    6: 574.5
  };
  function playTone(btn, len) {
    o.frequency.value = freqMap[btn];
    g.gain.setTargetAtTime(volume, context.currentTime + 0.05, 0.025);
    tonePlaying = true;
    setTimeout(function() {
      stopTone();
    }, len);
  }
  function startTone(btn) {
    if (!tonePlaying) {
      o.frequency.value = freqMap[btn];
      g.gain.setTargetAtTime(volume, context.currentTime + 0.05, 0.025);
      tonePlaying = true;
    }
  }
  function stopTone() {
    g.gain.setTargetAtTime(0, context.currentTime + 0.05, 0.025);
    tonePlaying = false;
  }
  
  //Page Initialization
  g.connect(context.destination);
  g.gain.setValueAtTime(0, context.currentTime);
  o.connect(g);
  o.start(0);
  
  function lightButton(btn) {
    document.getElementById("button" + btn).classList.add("lit");
  }
  function clearButton(btn) {
    document.getElementById("button" + btn).classList.remove("lit");
  }
  
  function playSingleClue(btn) {
    if (gamePlaying) {
      lightButton(btn);
      playTone(btn, clueHoldTime);
      setTimeout(clearButton, clueHoldTime, btn);
    }
  }
  
  function playClueSequence() {
    guessCounter = 0;
  
    let delay = nextClueWaitTime; //set delay to initial wait time
    for (let i = 0; i <= progress; i++) {
      // for each clue that is revealed so far
      console.log("play single clue: " + pattern[i] + " in " + delay + "ms");
      setTimeout(playSingleClue, delay, pattern[i]); // set a timeout to play that clue
      delay += clueHoldTime;
      delay += cluePauseTime;
    }
  }
  
  function loseGame() {
    stopGame();
    alert("Game Over. You lost.");
  }
  
  function winGame() {
    stopGame();
    alert("Congratulations! You won!");
  }
  
  function guess(btn) {
    console.log("user guessed: " + btn);
    if (!gamePlaying) {
      return;
    }
  
    if (pattern[guessCounter] == btn) {
      //Guess was correct!
      if (guessCounter == progress) {
        if (progress == pattern.length - 1) {
          //GAME OVER: WIN!
          winGame();
        } else {
          //Pattern correct. Add next segment
          progress++;
          playClueSequence();
        }
      } else {
        //so far so good... check the next guess
        guessCounter++;
      }
    } else {
      //Guess was incorrect
      //GAME OVER: LOSE!
      loseGame();
    }
  }
  