diff --git a/dampedAndDrivenSpring.html b/dampedAndDrivenSpring.html
new file mode 100644
index 0000000..f6f2d29
--- /dev/null
+++ b/dampedAndDrivenSpring.html
@@ -0,0 +1,273 @@
+<!--
+    This work is licensed under CC BY-NC-ND 4.0            
+    Link to license: http://creativecommons.org/licenses/by-nc-nd/4.0/
+    Attribute to Russell Georgi
+-->
+<html>
+    <head>
+        <title>
+            Damped and driven spring
+        </title>
+        <style>
+            .container
+            {
+                position: relative;
+            }
+            #caseOneButton
+            {
+                left: 12.5px;
+                top: 12.5px;
+                width: 100px;
+                height: 50px;
+                position: absolute;
+            }
+            #caseTwoButton
+            {
+                left: 12.5px;
+                top: 75px;
+                width: 100px;
+                height: 50px;
+                position: absolute;
+            }
+            #caseThreeButton
+            {
+                left: 12.5px;
+                top: 137.5px;
+                width: 100px;
+                height: 50px;
+                position: absolute;
+            }
+            #caseFourButton
+            {
+                left: 12.5px;
+                top: 200px;
+                width: 100px;
+                height: 50px;
+                position: absolute;
+            }
+
+            canvas
+            {
+                position: absolute;
+            }
+
+            html, body {
+                width:  100%;
+                height: 100%;
+                margin: 0px;
+                border: 0;
+                overflow: hidden;
+                display: block;
+            }
+        </style>
+    </head>
+    <body>       
+        <canvas id="myCanvas" width="1" height="1" style="border:1px solid #ffffff;"></canvas>
+        <div class="container">
+            <button type="button" id="caseOneButton" onclick="Case1()">&#969/&#969&#8320 = 0.5</button>
+            <button type="button" id="caseTwoButton" onclick="Case2()">&#969/&#969&#8320 = 0.75</button>
+            <button type="button" id="caseThreeButton" onclick="Case3()">&#969/&#969&#8320 = 1</button>
+            <button type="button" id="caseFourButton" onclick="Case4()">&#969/&#969&#8320 = 2</button>
+        </div> 
+    
+        
+        <script>
+        var c = document.getElementById("myCanvas");
+        var ctx = c.getContext("2d");
+        ctx.canvas.width = window.innerWidth;
+        ctx.canvas.height = window.innerHeight;
+
+        function Clear(ctx)
+        {
+            ctx.clearRect(-c.width, -c.height, c.width * 2, c.height * 2);
+        }
+
+        var cl = 11;
+        var clc = 12;
+        var dt = .025;
+        var o = 1.5;
+        var g = .5;
+        var dom = .1;
+        var bottom = 0;
+        var side = 350;
+        var dh = 150;
+        var dr = -50;
+        var h = 10;
+        var k = 90;
+        var m = 10;
+        var v = 0;
+        var dis = 0;
+        var phi = 0;
+        var i = 1;
+        var t = 0;
+        var xPos = -20;
+        var yPos = 00;
+        var amp = 0;
+        var pause = false;
+        var steadyStadeReps = 400;
+        var o0 = Math.sqrt(k/m);
+        CalculateInitialValues();
+        ctx.translate(ctx.canvas.width / 2, ctx.canvas.height / 2)
+        ctx.scale(3, 3);
+
+        function Update()
+        {
+            if (!pause)
+            {
+                dis += v * dt;
+                var stretch = (-h*Math.cos(o*t - phi) + dis)
+                v += ((-stretch * k * dt / m) + (-v * g * dt));
+                Draw();
+                t = t + dt;
+                ctx.strokeStyle = "#000000";
+            }
+            setTimeout(Update, 1000/120);
+        }
+
+        Update();
+
+        function Case1()
+        {
+            o = Math.sqrt(k/m) * 0.5;
+            CalculateInitialValues();
+        }
+
+        function Case2()
+        {
+            o = Math.sqrt(k/m) * 0.75;
+            CalculateInitialValues();
+        }
+
+        function Case3()
+        {
+            o = Math.sqrt(k/m);
+            CalculateInitialValues();
+        }
+
+        function Case4()
+        {
+            o = Math.sqrt(k/m) * 2;
+            CalculateInitialValues();
+        }
+
+        function Draw()
+        {
+            Clear(ctx);
+            var x1 = dr + h*Math.cos(o*t);
+            var a = (h*(o0^2 - o^2))/((o0^2 - o^2)^2 + g^2 * o^2)
+            var b = (h*(g*o))/((o0^2 - o^2)^2 + g^2 * o^2)
+            var x2 = dh + dr + dis
+            if (x2 > amp)
+            {
+                amp = x2;
+            }
+            ctx.beginPath();
+            ctx.moveTo(dr + xPos, -10 + yPos);
+            ctx.lineTo(dr + xPos, yPos);
+            ctx.stroke();
+            ctx.beginPath();
+            ctx.moveTo(dh + dr + xPos, -10 + yPos);
+            ctx.lineTo(dh + dr + xPos, yPos);
+            ctx.stroke();
+            ctx.beginPath();
+            ctx.moveTo(h + dr + xPos, -10 + yPos);
+            ctx.lineTo(h + dr + xPos, yPos);
+            ctx.stroke();
+            ctx.beginPath();
+            ctx.moveTo(dh + dr + (k*h/m)/(g*o0) + xPos, -10 + yPos);
+            ctx.lineTo(dh + dr + (k*h/m)/(g*o0) + xPos, 0 + yPos);
+            ctx.stroke();
+            ctx.beginPath();
+            ctx.moveTo(-h + dr + xPos, -10 + yPos);
+            ctx.lineTo(-h + dr + xPos, yPos);
+            ctx.stroke();
+            ctx.beginPath();
+            ctx.moveTo(dh + dr - (k*h/m)/(g*o0) + xPos, -10 + yPos);
+            ctx.lineTo(dh + dr - (k*h/m)/(g*o0) + xPos, yPos);
+            ctx.stroke();
+            var dx = (x2 - x1) / 3;
+            /*ctx.beginPath();
+            ctx.moveTo(x1 + 10 + xPos, -30 + yPos);
+            ctx.lineTo(x1 + dx + xPos, -20 + yPos);
+            ctx.stroke();
+            ctx.beginPath();
+            ctx.moveTo(x1 + dx + xPos, -20 + yPos);
+            ctx.lineTo(x1 + dx + dx + xPos, -40 + yPos);
+            ctx.stroke();
+            ctx.beginPath();
+            ctx.moveTo(x1 + dx + dx + xPos, -40 + yPos);
+            ctx.lineTo(x2 - 10 + xPos, -30 + yPos);
+            ctx.stroke();*/
+            drawSpring(1, 3, (x2 - 10) - (x1 + 10), 10, 10, x1 + 10 + xPos, -30 + yPos, 0.1);
+            ctx.fillStyle = "#ffffff";
+            ctx.beginPath();
+            ctx.arc(x1 + xPos, -30 + yPos, 10, 0, Math.PI * 2);
+            ctx.fill();
+            ctx.beginPath();
+            ctx.arc(x2 + xPos, -30 + yPos, 10, 0, Math.PI * 2);
+            ctx.fill();
+            ctx.beginPath();
+            ctx.arc(x1 + xPos, -30 + yPos, 10, 0, Math.PI * 2);
+            ctx.stroke();
+            ctx.beginPath();
+            ctx.arc(x2 + xPos, -30 + yPos, 10, 0, Math.PI * 2);
+            ctx.stroke();
+        }
+
+        function Reset()
+        {
+            pause = !pause;
+        }
+
+        function drawSpring(a, b, xSize, ySize, numLoops, x, y, tStep)
+        {
+            var tStart = Math.PI / 2;
+            var tEnd = (3 * Math.PI / 2) + (2 * Math.PI * numLoops);
+            var xEnd = a * tEnd - b * Math.sin(tEnd);
+            var yEnd = a + b;
+            var xFactor = xSize / xEnd;
+            var yFactor = ySize / yEnd;
+            var xShift = x - a * (Math.PI / 2) + b * Math.sin(Math.PI / 2);
+            var yShift = y - a + b * Math.cos(Math.PI / 2);
+            for (p = tStart; p <= tEnd; p += tStep)
+            {
+                ctx.beginPath();
+                ctx.moveTo(xShift + xFactor * (a * p - b * Math.sin(p)), yShift + yFactor * (a - b * Math.cos(p)));
+                ctx.lineTo(xShift + xFactor * (a * (p + tStep) - b * Math.sin(p + tStep)), yShift + yFactor * (a - b * Math.cos(p + tStep)));
+                ctx.stroke();
+            }
+        }
+
+        function CalculateInitialValues()
+        {
+            /*var a = ((k*h/m)*(o0^2 - o^2))/((o0^2 - o^2)^2 + g^2 * o^2);
+            var b = ((k*h/m)*(g*o))/((o0^2 - o^2)^2 + g^2 * o^2);
+            phi = Math.atan(b/a);
+            if (a < 0)
+            {
+                phi += Math.PI;
+            }
+            dis = 0;
+            v = o * ((k*h/m)/(g*o0));*/
+            for (j = 0; j < steadyStadeReps; j++)
+            {
+                dis += v * dt;
+                var stretch = (-h*Math.cos(o*t - phi) + dis)
+                v += ((-stretch * k * dt / m) + (-v * g * dt));
+                t = t + dt;
+            }
+        }
+
+        window.addEventListener('resize', function(event) {
+            c.width = window.innerWidth;
+            c.height = window.innerHeight;
+            ctx.translate(c.width / 2, c.height / 2);
+            ctx.scale(3, 3);
+        }, true);
+
+        </script>
+    </body>
+    <p xmlns:cc="http://creativecommons.org/ns#" style="font-size: 1vw; bottom: 0px; position: absolute;">
+        This work is licensed under 
+        <a href="http://creativecommons.org/licenses/by-nc-nd/4.0/?ref=chooser-v1" target="_blank" rel="license noopener noreferrer" style="display:inline-block;">CC BY-NC-ND 4.0<img style="height:22px!important;margin-left:3px;vertical-align:text-bottom;" src="https://mirrors.creativecommons.org/presskit/icons/cc.svg?ref=chooser-v1"><img style="height:22px!important;margin-left:3px;vertical-align:text-bottom;" src="https://mirrors.creativecommons.org/presskit/icons/by.svg?ref=chooser-v1"><img style="height:22px!important;margin-left:3px;vertical-align:text-bottom;" src="https://mirrors.creativecommons.org/presskit/icons/nc.svg?ref=chooser-v1"><img style="height:22px!important;margin-left:3px;vertical-align:text-bottom;" src="https://mirrors.creativecommons.org/presskit/icons/nd.svg?ref=chooser-v1"></a></p>
+</html>
\ No newline at end of file
diff --git a/index.html b/index.html
index 5c998bb..78e609c 100644
--- a/index.html
+++ b/index.html
@@ -163,6 +163,27 @@
                     <t>Nope, one more</t>
                 </td>
             </tr>
+            <tr>
+                <th colspan = "2">
+                    <t>Chapter 4: Oscillations</t>
+                </th>
+            </tr>
+            <tr>
+                <td>
+                    <a href='dampedAndDrivenSpring.html'>Damped and driven spring</a>
+                </td>
+                <td>
+                    <t>Damped and driven spring resonance example</t>
+                </td>
+            </tr>
+            <tr>
+                <td>
+                    <a href='twoMassesThreeSprings.html'>Two masses, three springs</a>
+                </td>
+                <td>
+                    <t>Other example problem from chapter 4</t>
+                </td>
+            </tr>
         </table>
         <p xmlns:cc="http://creativecommons.org/ns#" >
             This work is licensed under 
diff --git a/twoMassesThreeSprings.html b/twoMassesThreeSprings.html
new file mode 100644
index 0000000..9ce1c91
--- /dev/null
+++ b/twoMassesThreeSprings.html
@@ -0,0 +1,157 @@
+<!--
+    This work is licensed under CC BY-NC-ND 4.0            
+    Link to license: http://creativecommons.org/licenses/by-nc-nd/4.0/
+    Attribute to Russell Georgi
+-->
+<html>
+    <head>
+        <title>
+            Two masses, three springss
+        </title>
+        <style>
+            html, body {
+                width:  100%;
+                height: 100%;
+                margin: 0px;
+                border: 0;
+                overflow: hidden;
+                display: block;
+            }
+
+            canvas {
+                position: absolute;
+            }
+
+                        
+            .dropbtn {
+              background-color: #04AA6D;
+              color: white;
+              padding: 16px;
+              font-size: 16px;
+              border: none;
+            }
+            
+            .dropdown {
+              position: absolute;
+              display: inline-block;
+            }
+            
+            .dropdown-content {
+              display: none;
+              position: relative;
+              background-color: #f1f1f1;
+              box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
+              z-index: 1;
+            }
+            
+            .dropdown-content button {
+              color: black;
+              padding: 12px 16px;
+              width: 100px;
+              text-decoration: none;
+              display: block;
+            }
+            
+            .dropdown-content a:hover {background-color: #ddd;}
+            
+            .dropdown:hover .dropdown-content {display: block;}
+            
+            .dropdown:hover .dropbtn {background-color: #3e8e41;}
+        </style>
+    </head>
+    <body>       
+        <canvas id="myCanvas" width="1" height="1" style="border:1px solid #ffffff;">
+        Your browser does not support the HTML5 canvas tag.</canvas>
+        <div class="dropdown">
+            <button class="dropbtn" id="btn">Mode 1</button>
+            <div class="dropdown-content">
+              <button onclick="num(0)">Mode 1</button>
+              <button onclick="num(1)">Mode 2</button>
+            </div>
+        </div>  
+        
+        <script>
+        var c = document.getElementById("myCanvas");
+        var ctx = c.getContext("2d");
+        ctx.canvas.width = window.innerWidth;
+        ctx.canvas.height = window.innerHeight;
+    
+        var w = 1;
+        var amp = 20;
+        var mode = 0;
+        var t = 0;
+        var dt = 0.1;
+        var xPos = 0;
+        var yPos = 0;
+
+        function num(n)
+        {
+            mode = n;
+        }
+
+
+        ctx.translate(ctx.canvas.width / 2, ctx.canvas.height / 2);
+        ctx.scale(1.5, 1.5);
+
+
+        function Clear(ctx)
+        {
+            ctx.clearRect(-c.width, -c.height, c.width * 2, c.height * 2);
+        }
+
+        function Update()
+        {
+            Draw();
+            t += dt;
+            setTimeout(Update, 1000/60)
+        }
+
+        function Draw()
+        {
+            Clear(ctx);
+            ctx.beginPath();
+            ctx.arc(xPos + 50 + amp * Math.sin((w + (mode * (Math.sqrt(3) - 1))) * t), yPos, 5, 0, Math.PI * 2);
+            ctx.fill();
+            ctx.beginPath();
+            ctx.arc(xPos - 50 + (1 - 2 * mode) * amp * Math.sin((w + (mode * (Math.sqrt(3) - 1))) * t), yPos, 5, 0, Math.PI * 2);
+            ctx.fill();
+            drawSpring(1, 3, 100 + 2 * mode * amp * Math.sin((w + (mode * (Math.sqrt(3) - 1))) * t), 10, 5, xPos - 50 + (1 - 2 * mode) * amp * Math.sin((w + (mode * (Math.sqrt(3) - 1))) * t), yPos, 0.1, 0);
+            drawSpring(1, 3, 100 + (1 - mode) * amp * Math.sin((w + (mode * (Math.sqrt(3) - 1))) * t) -  mode * amp * Math.sin((w + (mode * (Math.sqrt(3) - 1))) * t), 10, 5, xPos - 150, yPos, 0.1, 0);
+            drawSpring(1, 3, 100 - amp * Math.sin((w + (mode * (Math.sqrt(3) - 1))) * t) , 10, 5, xPos + 50 + amp * Math.sin((w + (mode * (Math.sqrt(3) - 1))) * t), yPos, 0.1, 0);
+        }
+
+        function drawSpring(a, b, xSize, ySize, numLoops, x, y, tStep, deltaY)
+        {
+            var tStart = Math.PI / 2;
+            var tEnd = (3 * Math.PI / 2) + (2 * Math.PI * numLoops);
+            var xEnd = a * tEnd - b * Math.sin(tEnd);
+            var yEnd = a + b;
+            var xFactor = xSize / xEnd;
+            var yFactor = ySize / yEnd;
+            var xShift = x - a * (Math.PI / 2) + b * Math.sin(Math.PI / 2);
+            var yShift = y - a + b * Math.cos(Math.PI / 2);
+            var slope = deltaY / xSize;
+            for (p = tStart; p <= tEnd; p += tStep)
+            {
+                ctx.beginPath();
+                ctx.moveTo(xShift + xFactor * (a * p - b * Math.sin(p)), yShift + yFactor * (a - b * Math.cos(p)) + slope * (a * p - b * Math.sin(p)));
+                ctx.lineTo(xShift + xFactor * (a * (p + tStep) - b * Math.sin(p + tStep)), yShift + yFactor * (a - b * Math.cos(p + tStep)));
+                ctx.stroke();
+            }
+        }
+
+        window.addEventListener('resize', function(event) {
+            c.width = window.innerWidth;
+            c.height = window.innerHeight;
+            ctx.translate(c.width / 2, c.height / 2);
+            ctx.scale(1.5, 1.5);
+        }, true);
+
+        Update();
+
+        </script>
+    </body>
+    <p xmlns:cc="http://creativecommons.org/ns#" style="font-size: 1vw; bottom: 0px; position: absolute;">
+        This work is licensed under 
+        <a href="http://creativecommons.org/licenses/by-nc-nd/4.0/?ref=chooser-v1" target="_blank" rel="license noopener noreferrer" style="display:inline-block;">CC BY-NC-ND 4.0<img style="height:22px!important;margin-left:3px;vertical-align:text-bottom;" src="https://mirrors.creativecommons.org/presskit/icons/cc.svg?ref=chooser-v1"><img style="height:22px!important;margin-left:3px;vertical-align:text-bottom;" src="https://mirrors.creativecommons.org/presskit/icons/by.svg?ref=chooser-v1"><img style="height:22px!important;margin-left:3px;vertical-align:text-bottom;" src="https://mirrors.creativecommons.org/presskit/icons/nc.svg?ref=chooser-v1"><img style="height:22px!important;margin-left:3px;vertical-align:text-bottom;" src="https://mirrors.creativecommons.org/presskit/icons/nd.svg?ref=chooser-v1"></a></p>
+</html>
\ No newline at end of file
