diff --git a/01 - JavaScript Drum Kit/index-START.html b/01 - JavaScript Drum Kit/index-START.html
index 4070d32767..ad91c76725 100644
--- a/01 - JavaScript Drum Kit/index-START.html	
+++ b/01 - JavaScript Drum Kit/index-START.html	
@@ -58,6 +58,23 @@
   <audio data-key="76" src="sounds/tink.wav"></audio>
 
 <script>
+function playSound(e) {
+  const audio = document.querySelector(`audio[data-key="${e.keyCode}"]`);
+  if(!audio) return;
+  audio.currentTime = 0;
+  audio.play();
+  const key = document.querySelector(`.key[data-key="${e.keyCode}"]`);
+  key.classList.add('playing');
+};
+
+function removeTransition(e) {
+  if (e.propertyName !== 'transform') return;
+  this.classList.remove('playing');
+}
+
+const keys = document.querySelectorAll('.key');
+keys.forEach(key => key.addEventListener('transitionend', removeTransition));
+window.addEventListener('keydown', playSound);
 
 </script>
 
diff --git a/02 - JS + CSS Clock/index-START.html b/02 - JS + CSS Clock/index-START.html
index 2712384201..826755e396 100644
--- a/02 - JS + CSS Clock/index-START.html	
+++ b/02 - JS + CSS Clock/index-START.html	
@@ -61,12 +61,30 @@
       background:black;
       position: absolute;
       top:50%;
+      transform-origin: 100%;
+      transition: all .05s;
+      transition-timing-function: cubic-bezier(.1 2.7 .58 1);
     }
 
   </style>
 
   <script>
+  const secondHand = document.querySelector('.second-hand');
+  const minuteHand = document.querySelector('.min-hand');
+  const hourHand = document.querySelector('.hour-hand');
 
+  function setDate() {
+    const now = new Date();
+    const secondDegree = ((now.getSeconds() / 60) * 360) + 90;
+    const minuteDegree = ((now.getMinutes() / 60) * 360) + 90;
+    const hourDegree = ((now.getHours() / 12) * 360) + 90;
+
+    secondHand.style.transform = `rotate(${secondDegree}deg)`;
+    minuteHand.style.transform = `rotate(${minuteDegree}deg)`;
+    hourHand.style.transform = `rotate(${hourDegree}deg)`;
+  }
+
+  setInterval(setDate, 1000);
 
   </script>
 </body>
diff --git a/03 - CSS Variables/index-START.html b/03 - CSS Variables/index-START.html
index 7171607a8b..d9c90c3245 100644
--- a/03 - CSS Variables/index-START.html	
+++ b/03 - CSS Variables/index-START.html	
@@ -21,7 +21,21 @@ <h2>Update CSS Variables with <span class='hl'>JS</span></h2>
   <img src="https://source.unsplash.com/7bwQXzbF6KE/800x500">
 
   <style>
+    :root {
+      --base: yellow;
+      --spacing: 10px;
+      --blur: 10px;
+    }
+
+    img {
+      padding: var(--spacing);
+      background: var(--base);
+      filter: blur(var(--blur));
+    }
 
+    .hl {
+      color: var(--base);
+    }
     /*
       misc styles, nothing to do with CSS variables
     */
@@ -48,6 +62,15 @@ <h2>Update CSS Variables with <span class='hl'>JS</span></h2>
   </style>
 
   <script>
+  const inputs = document.querySelectorAll('.controls input');
+
+  function handleUpdate() {
+    const suffix = this.dataset.sizing || '';
+    document.documentElement.style.setProperty(`--${this.name}`, this.value + suffix);
+  };
+  inputs.forEach(input => input.addEventListener('change', handleUpdate));
+  inputs.forEach(input => input.addEventListener('mousemove', handleUpdate));
+  // console.log(inputs);
   </script>
 
 </body>
diff --git a/04 - Array Cardio Day 1/index-START.html b/04 - Array Cardio Day 1/index-START.html
index 4162bce339..07bf906ac0 100644
--- a/04 - Array Cardio Day 1/index-START.html	
+++ b/04 - Array Cardio Day 1/index-START.html	
@@ -33,28 +33,48 @@
 
     // Array.prototype.filter()
     // 1. Filter the list of inventors for those who were born in the 1500's
+    const fifteen = inventors.filter(inv => Math.floor(inv.year / 100) === 15);
+    // console.table(fifteen);
 
     // Array.prototype.map()
     // 2. Give us an array of the inventors' first and last names
+    const first = inventors.map(inv => inv.first + ' ' + inv.last);
+    // console.log(first);
 
     // Array.prototype.sort()
     // 3. Sort the inventors by birthdate, oldest to youngest
+    const youngest = inventors.sort((a,b) => a.year > b.year ? 1 : -1);
+    // console.table(youngest);
 
     // Array.prototype.reduce()
     // 4. How many years did all the inventors live?
+    const totLife = inventors.reduce((total, inv) => total + inv.passed - inv.year, 0);
+    // console.log(totLife);
 
     // 5. Sort the inventors by years lived
+    const age = inventors.sort((a,b) => a.passed - a.year < b.passed - b.year ? 1 : -1);
+    // console.table(age);
 
     // 6. create a list of Boulevards in Paris that contain 'de' anywhere in the name
     // https://en.wikipedia.org/wiki/Category:Boulevards_in_Paris
 
+    const streets = [...document.querySelectorAll('.mw-category a')]
+                      .map(el => el.innerText)
+                      .filter(name => name.includes('de'));
 
     // 7. sort Exercise
     // Sort the people alphabetically by last name
+    const last = people.sort((a,b) => a.split(',')[0] > b.split(',')[0] ? 1 : -1);
+    // console.log(last);
 
     // 8. Reduce Exercise
     // Sum up the instances of each of these
     const data = ['car', 'car', 'truck', 'truck', 'bike', 'walk', 'car', 'van', 'bike', 'walk', 'car', 'van', 'car', 'truck' ];
+    const trans = data.reduce((obj, item) => {
+      obj[item] ? obj[item]++ : obj[item] = 1;
+      return obj;
+    }, {});
+    console.log(trans);
 
   </script>
 </body>