diff --git a/01 - JavaScript Drum Kit/index-START.html b/01 - JavaScript Drum Kit/index-START.html
index 4070d32767..964edd0a29 100644
--- a/01 - JavaScript Drum Kit/index-START.html	
+++ b/01 - JavaScript Drum Kit/index-START.html	
@@ -58,6 +58,24 @@
   <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;
+  audio.currentTime = 0;
+  audio.play();
+  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..361fece9f8 100644
--- a/02 - JS + CSS Clock/index-START.html	
+++ b/02 - JS + CSS Clock/index-START.html	
@@ -61,12 +61,37 @@
       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();
+    const seconds = now.getSeconds();
+    const secondsDegrees = ((seconds / 60) * 360) + 90;
+    secondHand.style.transform = `rotate(${secondsDegrees}deg)`;
+
+    const mins = now.getMinutes();
+    const minsDegrees = ((mins / 60 ) * 360 )+ 90;
+    hourHand.style.transform = `rotate(${minsDegrees}deg)`;
+
+    const hour = now.getHours();
+    const hourDegrees = ((mins / 12) * 360) + 90;
+    hourHand.style.transform = `rotate(${hourDegrees}deg)`;
+
+  }
+
+  setInterval(setDate, 1000);
 
   </script>
 </body>
diff --git a/03 - CSS Variables/index-START.html b/03 - CSS Variables/index-START.html
index 7171607a8b..d7432aba7f 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: #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
     */
@@ -48,6 +62,17 @@ <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 4162bce339..f87be4b01a 100644
--- a/04 - Array Cardio Day 1/index-START.html	
+++ b/04 - Array Cardio Day 1/index-START.html	
@@ -33,29 +33,74 @@
 
     // 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.log(fullNames);
 
     // Array.prototype.sort()
     // 3. Sort the inventors by birthdate, oldest to youngest
+    /*
+    const ordered = inventors.sort(function(a, b){
+      if (a.year > b.year){
+        return 1;
+      } else{
+        return -1;
+      }
+    });*/
+
+    const ordered = inventors.sort((a, b) => a.year > b.year ? 1 : -1);
+    console.table(ordered);
 
     // 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(function(a,b){
+      const lastGuy = a.passed - a.year;
+      const nextGuy = b.passed - b.year;
 
+      return lastGuy > nextGuy ? -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 = [...category.querySelectorAll('a')];
+    const de = links
+                .map(link => link.textContent)
+                .filter(streetName => streetName.includes('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.log(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(function(obj, item){
+      if(!obj[item]){
+        obj[item] = 0;
+      }
+      obj[item]++;
+      return obj;
+    }, {});
+    console.log(transportation);
+
   </script>
 </body>
 </html>