diff --git a/01 - JavaScript Drum Kit/index-START.html b/01 - JavaScript Drum Kit/index-START.html
index 4070d32767..dc613a694d 100644
--- a/01 - JavaScript Drum Kit/index-START.html	
+++ b/01 - JavaScript Drum Kit/index-START.html	
@@ -58,6 +58,25 @@
   <audio data-key="76" src="sounds/tink.wav"></audio>
 
 <script>
+  function playSound(e) {
+    const audio = document.querySelector(`audio[data-key="${e.keyCode}"]`);
+    const key = document.querySelector(`.key[data-key="${e.keyCode}"]`);
+
+    if (!audio) return; // Finish function, if no audio is found.
+    audio.currentTime = 0; // Rewind to start of audio.
+    audio.play();
+
+    key.classList.add('playing');
+  }
+
+  function removeTransition(e) {
+    if(e.propertyName !== 'transform') return; // Skip if not a transform transition.
+    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 and CSS Clock/index-START.html b/02 - JS and CSS Clock/index-START.html
index ee7eaefb1f..ff33e27ed7 100644
--- a/02 - JS and CSS Clock/index-START.html	
+++ b/02 - JS and CSS Clock/index-START.html	
@@ -62,13 +62,39 @@
       background:black;
       position: absolute;
       top:50%;
+      transform-origin: 100%;
+      transform: rotate(90deg);
+      transition: all 0.05s;
+      transition-timing-function: cubic-bezier(0.1, 2.7, 0.58, 1);
     }
 
   </style>
 
   <script>
+    const secondHand = document.querySelector('.second-hand');
+    const minsHand = document.querySelector('.min-hand');
+    const hourHand = document.querySelector('.hour-hand');
 
+    function setDate() {
+      const now = new Date();
 
+      // Seconds
+      const seconds = now.getSeconds();
+      const secondsDegrees = ((seconds / 60) * 360) + 90;
+      secondHand.style.transform = `rotate(${secondsDegrees}deg)`;
+
+      // Minutes
+      const mins = now.getMinutes();
+      const minsDegrees = ((mins / 60) * 360) + 90;
+      minsHand.style.transform = `rotate(${minsDegrees}deg)`;
+
+      // hours
+      const hours = now.getHours();
+      const hoursDegrees = ((hours / 12) * 360) + 90;
+      hourHand.style.transform = `rotate(${hoursDegrees}deg)`;
+    }
+
+    setInterval(setDate, 1000);
   </script>
 </body>
 </html>
diff --git a/03 - CSS Variables/index-START.html b/03 - CSS Variables/index-START.html
index 8a4f0d556e..964127beac 100644
--- a/03 - CSS Variables/index-START.html	
+++ b/03 - CSS Variables/index-START.html	
@@ -22,6 +22,22 @@ <h2>Update CSS Variables with <span class='hl'>JS</span></h2>
 
   <style>
 
+    :root {
+      --base: #ffc600;
+      --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
     */
@@ -45,6 +61,15 @@ <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));
+
   </script>
 
 </body>
diff --git a/04 - Array Cardio Day 1/index-START.html b/04 - Array Cardio Day 1/index-START.html
index eec0ffc31d..1efa75a24c 100644
--- a/04 - Array Cardio Day 1/index-START.html	
+++ b/04 - Array Cardio Day 1/index-START.html	
@@ -31,29 +31,67 @@
 
     // Array.prototype.filter()
     // 1. Filter the list of inventors for those who were born in the 1500's
+    const fifteen = inventors.filter(inventor => (inventor.year >= 1500 && inventor.year < 1600));
+    console.table(fifteen);
 
     // Array.prototype.map()
     // 2. Give us an array of the inventors' first and last names
+    const fullNames = inventors.map(inventor => `${inventor.first} ${inventor.last}`);
+    console.table(fullNames);
 
     // Array.prototype.sort()
     // 3. Sort the inventors by birthdate, oldest to youngest
+    const sort = inventors.sort((a, b) => a.year > b.year ? 1: -1);
+    console.table(sort);
 
     // Array.prototype.reduce()
     // 4. How many years did all the inventors live?
+    const totalYears = inventors.reduce((total, inventor) => {
+      return total + (inventor.passed - inventor.year);
+    }, 0);
+    console.log(totalYears);
 
     // 5. Sort the inventors by years lived
+    const oldest = inventors.sort((a, b) => {
+      const lastGuy = a.passed - a.year;
+      const newGuy = b.passed - b.year;
+      return lastGuy > newGuy ? -1 : 1;
+    });
+    console.table(oldest);
 
     // 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 category = document.querySelector('.mw-category');
+    // const links = Array.from(category.querySelectorAll('a'));
+    // const de = links
+    //             .map(link => link.textContent)
+    //             .filter(streetName => streetName.includes('de'));
+
+    // console.log(de);
 
 
     // 7. sort Exercise
     // Sort the people alphabetically by last name
+    const alpha = people.sort((lastOne, nextOne) => {
+      const [aLast, aFirst] = lastOne.split(', ');
+      const [bLast, bFirst] = nextOne.split(', ');
+      return aLast > bLast ? 1 : -1;
+    });
+    console.table(alpha);
 
     // 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 transportation = data.reduce((obj, item) => {
+      if(!obj[item]) {
+        obj[item] = 0;
+      }
+      obj[item]++;
+      return obj;
+    }, {});
+    console.log(transportation);
+
   </script>
 </body>
 </html>