diff --git a/component/ChartOrSandbox.tsx b/component/ChartOrSandbox.tsx
index f27e70977..8c5c8429b 100644
--- a/component/ChartOrSandbox.tsx
+++ b/component/ChartOrSandbox.tsx
@@ -13,6 +13,7 @@ type ChartOrSandboxProps = {
   height?: number;
   maxWidth?: number;
   caption?: string | ReactNode;
+  fileToOpen?: string;
 };
 
 export const ChartOrSandbox = ({
@@ -21,6 +22,7 @@ export const ChartOrSandbox = ({
   height = 400,
   maxWidth = 800,
   caption,
+  fileToOpen,
 }: ChartOrSandboxProps) => {
   const [showSandbox, setShowSandbox] = useState(false);
 
@@ -38,7 +40,7 @@ export const ChartOrSandbox = ({
       {showSandbox ? (
         <div className="flex flex-col items-center justify-center w-full">
           <div style={{ maxWidth: 2000 }} className="w-full z-50">
-            <CodeSandbox vizName={vizName} />
+            <CodeSandbox vizName={vizName} fileToOpen={fileToOpen} />
           </div>
           <div className="flex justify-center mt-2">
             <Button size="sm" onClick={() => setShowSandbox(!showSandbox)}>
diff --git a/pages/course/animation/react-spring-for-dataviz.tsx b/pages/course/animation/react-spring-for-dataviz.tsx
index 2fb452bc4..e813163f8 100644
--- a/pages/course/animation/react-spring-for-dataviz.tsx
+++ b/pages/course/animation/react-spring-for-dataviz.tsx
@@ -22,7 +22,7 @@ import {
   ExerciseDoubleSandbox,
 } from '@/component/ExerciseDoubleSandbox';
 import { ExerciseAccordion } from '@/component/ExerciseAccordion';
-import { Graph14 } from '@/viz/exercise/AnimationSimpleCircleSolution/Graph';
+import { Graph11 } from '@/viz/exercise/AnimationSimpleDivSolution/Graph';
 
 const previousURL = '/course/animation/introduction';
 const currentURL = '/course/animation/react-spring-for-dataviz';
@@ -234,6 +234,7 @@ export const Circle = ({ position }) => {
         maxWidth={800}
         height={200}
         caption="A very basic animation using react and react-spring."
+        fileToOpen={'Circle.tsx'}
       />
 
       <Accordion type="single" collapsible>
@@ -304,6 +305,7 @@ const springProps = useSpring({
             feel. Try them in this sandbox!
           </p>
         }
+        fileToOpen={'Circle.tsx'}
       />
       <p>To use one of the presets, you can do something like this:</p>
       <CodeBlock
@@ -382,6 +384,7 @@ return (
         maxWidth={800}
         height={200}
         caption="Smooth animation where circle size is derived from X position."
+        fileToOpen={'Circle.tsx'}
       />
 
       <h2>Animating Text</h2>
@@ -401,6 +404,7 @@ return (
         maxWidth={800}
         height={200}
         caption="Demo: react-spring can also animate text, colors and so much more!"
+        fileToOpen={'Circle.tsx'}
       />
 
       <h2>Exercises</h2>
@@ -445,28 +449,25 @@ const exercises: Exercise[] = [
   {
     whyItMatters: (
       <>
-        <p>
-          Let’s apply what we just learned by creating your first{' '}
-          <code>canvas</code> element, modifying it using a <code>ref</code> and{' '}
-          <code>useEffect</code>.
-        </p>
-        <p>And while we’re at it, let’s explore how to adjust opacity!</p>
+        <p>Just applying the very basic usage we just learned</p>
       </>
     ),
     toDo: (
       <>
         <ul>
           <li>
-            Use <code>useRef()</code> to create a ref targeting the canvas
-            element.
+            Create a <code>Circle.tsx</code> file that makes a{' '}
+            <code>Circle</code> component
           </li>
           <li>
-            Add a <code>useEffect()</code> hook to draw a blue circle on the
-            canvas.
+            Create a <code>position</code> state in <code>Graph.tsx</code>. Each
+            time the user click on the SVG area, this position must toggle
+            between <code>40</code> and <code>width - 40</code>
           </li>
           <li>
-            Adjust the circle’s opacity with the <code>globalAlpha</code>{' '}
-            property.
+            Provide the position to the <code>Circle</code> component. Render a
+            circle at this <code>x</code> position, animate its movement with{' '}
+            <code>react-spring</code>.
           </li>
         </ul>
       </>
@@ -479,49 +480,67 @@ const exercises: Exercise[] = [
     whyItMatters: (
       <>
         <p>
-          Unlike SVG elements, strokes and fills must be drawn separately on the
-          canvas. 😱
+          react-spring can animate many sorts of values. Opacity is one of them,
+          but text, and colors work too!
         </p>
       </>
     ),
     toDo: (
       <>
         <ul>
-          <li>Draw a rectangle on the canvas.</li>
           <li>
-            Use <code>strokeRect()</code> and <code>fillRect()</code> to apply a
-            green stroke and fill it with pink.
+            Same as previous exercise, but add a property for the{' '}
+            <code>opacity</code>.
+          </li>
+          <li>
+            <code>opacity</code> must toggle between <code>0.2</code> and{' '}
+            <code>1</code> depending on if the circle is on the left or on the
+            right.
           </li>
         </ul>
       </>
     ),
-    practiceSandbox: 'exercise/CanvasRectOutlinePractice',
-    solutionSandbox: 'exercise/CanvasRectOutlineSolution',
+    practiceSandbox: 'exercise/AnimationDefaultPractice',
+    solutionSandbox: 'exercise/AnimationSimpleCircleOpacitySolution',
+    fileToOpen: 'Graph.tsx',
   },
   {
     whyItMatters: (
       <>
         <p>
-          When working with canvas drawings, you’ll often need to clear previous
-          content.{' '}
+          <code>react-spring</code> does not only work with SVG! HTML elements
+          can be animated too!
         </p>
         <p>
-          This is possible with <code>clearRect()</code>.
+          note also that the spring can be made directly in the{' '}
+          <code>Graph</code> component. Making a separate component to organise
+          your work is nice IMO, but not required.
         </p>
       </>
     ),
     toDo: (
       <>
         <ul>
-          <li>Draw a large circle on the canvas.</li>
           <li>
-            Use <code>clearRect()</code> to erase part of the circle.
+            In <code>Graph.tsx</code>, render a parent <code>div</code> using
+            the <code>width</code> and <code>height</code> provided at the top
+            of the component instead of the usual SVG area.
+          </li>
+          <li>
+            In this <code>div</code>, render another <code>div</code>. It must
+            be square, have a <code>backgroundColor</code> of <code>red</code>{' '}
+            and be absolutely positioned.
+          </li>
+          <li>
+            Now make the red <code>div</code> moves from right to left when user
+            clicks on the parent div.
           </li>
         </ul>
       </>
     ),
-    practiceSandbox: 'exercise/CanvasClearRectPractice',
-    solutionSandbox: 'exercise/CanvasClearRectSolution',
+    practiceSandbox: 'exercise/AnimationDefaultPractice',
+    solutionSandbox: 'exercise/AnimationSimpleDivSolution',
+    fileToOpen: 'Graph.tsx',
   },
   {
     whyItMatters: (
@@ -547,8 +566,9 @@ const exercises: Exercise[] = [
         </ul>
       </>
     ),
-    practiceSandbox: 'exercise/CanvasBasicLinePractice',
-    solutionSandbox: 'exercise/CanvasBasicLineSolution',
+    practiceSandbox: 'exercise/AnimationDefaultPractice',
+    solutionSandbox: 'exercise/AnimationSimpleCircleOpacitySolution',
+    fileToOpen: 'Graph.tsx',
   },
   {
     whyItMatters: (
@@ -571,8 +591,9 @@ const exercises: Exercise[] = [
         </ul>
       </>
     ),
-    practiceSandbox: 'exercise/CanvasTenCirclesPractice',
-    solutionSandbox: 'exercise/CanvasTenCirclesSolution',
+    practiceSandbox: 'exercise/AnimationDefaultPractice',
+    solutionSandbox: 'exercise/AnimationSimpleCircleOpacitySolution',
+    fileToOpen: 'Graph.tsx',
   },
   {
     whyItMatters: (
@@ -598,7 +619,8 @@ const exercises: Exercise[] = [
         </ul>
       </>
     ),
-    practiceSandbox: 'exercise/CanvasBasicTextPractice',
-    solutionSandbox: 'exercise/CanvasBasicTextSolution',
+    practiceSandbox: 'exercise/AnimationDefaultPractice',
+    solutionSandbox: 'exercise/AnimationSimpleCircleOpacitySolution',
+    fileToOpen: 'Graph.tsx',
   },
 ];
diff --git a/viz/ReactSpringText/index.js b/viz/ReactSpringText/index.js
index 2f7ae90af..dd6a2d70e 100644
--- a/viz/ReactSpringText/index.js
+++ b/viz/ReactSpringText/index.js
@@ -1,5 +1,5 @@
-import ReactDOM from "react-dom";
-import { ReactSpringMostBasic } from "./ReactSpringMostBasic";
+import ReactDOM from 'react-dom';
+import { ReactSpringTextDemo } from './ReactSpringTextDemo';
 
-const rootElement = document.getElementById("root");
-ReactDOM.render(<ReactSpringMostBasic width={800} height={300} />, rootElement);
+const rootElement = document.getElementById('root');
+ReactDOM.render(<ReactSpringTextDemo width={800} height={300} />, rootElement);
diff --git a/viz/exercise/AnimationSimpleCircleOpacitySolution/Circle.tsx b/viz/exercise/AnimationSimpleCircleOpacitySolution/Circle.tsx
new file mode 100644
index 000000000..d2d943bbb
--- /dev/null
+++ b/viz/exercise/AnimationSimpleCircleOpacitySolution/Circle.tsx
@@ -0,0 +1,25 @@
+import { animated, useSpring } from 'react-spring';
+
+type CircleVizProps = {
+  position: number;
+  color: string;
+  opacity: number;
+};
+
+export const Circle = ({ position, color, opacity }: CircleVizProps) => {
+  const springProps = useSpring({
+    to: { position, color, opacity },
+  });
+
+  return (
+    <animated.circle
+      strokeWidth={2}
+      fillOpacity={springProps.opacity}
+      r={38}
+      cy={50}
+      cx={springProps.position}
+      stroke={springProps.color}
+      fill={springProps.color}
+    />
+  );
+};
diff --git a/viz/exercise/AnimationSimpleCircleOpacitySolution/Graph.tsx b/viz/exercise/AnimationSimpleCircleOpacitySolution/Graph.tsx
new file mode 100644
index 000000000..82f96443f
--- /dev/null
+++ b/viz/exercise/AnimationSimpleCircleOpacitySolution/Graph.tsx
@@ -0,0 +1,25 @@
+import { useState } from 'react';
+import { Circle } from './Circle';
+
+const width = 500;
+const height = 300;
+
+export const Graph = () => {
+  const [position, setPosition] = useState(40);
+
+  return (
+    <svg
+      width={width}
+      height={height}
+      onClick={() => {
+        position > 100 ? setPosition(40) : setPosition(width - 50);
+      }}
+    >
+      <Circle
+        position={position}
+        color={position > 200 ? 'red' : 'blue'}
+        opacity={position > 200 ? 0.2 : 1}
+      />
+    </svg>
+  );
+};
diff --git a/viz/exercise/AnimationSimpleCircleOpacitySolution/index.js b/viz/exercise/AnimationSimpleCircleOpacitySolution/index.js
new file mode 100644
index 000000000..fa564d27f
--- /dev/null
+++ b/viz/exercise/AnimationSimpleCircleOpacitySolution/index.js
@@ -0,0 +1,6 @@
+// File used to render something in codesandbox only
+import ReactDOM from 'react-dom';
+import { Graph } from './Graph';
+
+const rootElement = document.getElementById('root');
+ReactDOM.render(<Graph />, rootElement);
diff --git a/viz/exercise/AnimationSimpleCircleOpacitySolution/package.json b/viz/exercise/AnimationSimpleCircleOpacitySolution/package.json
new file mode 100644
index 000000000..df56d88f4
--- /dev/null
+++ b/viz/exercise/AnimationSimpleCircleOpacitySolution/package.json
@@ -0,0 +1,31 @@
+{
+  "name": "pie-chart-basic",
+  "version": "1.0.0",
+  "description": "",
+  "keywords": [],
+  "main": "index.js",
+  "dependencies": {
+    "react": "17.0.2",
+    "d3": "7.1.1",
+    "react-dom": "17.0.2",
+    "react-scripts": "4.0.0",
+    "@react-spring/web": "^9.3.1",
+    "react-spring": "9.3.2"
+  },
+  "devDependencies": {
+    "@babel/runtime": "7.13.8",
+    "typescript": "4.1.3"
+  },
+  "scripts": {
+    "start": "react-scripts start",
+    "build": "react-scripts build",
+    "test": "react-scripts test --env=jsdom",
+    "eject": "react-scripts eject"
+  },
+  "browserslist": [
+    ">0.2%",
+    "not dead",
+    "not ie <= 11",
+    "not op_mini all"
+  ]
+}
diff --git a/viz/exercise/AnimationSimpleDivSolution/Circle.tsx b/viz/exercise/AnimationSimpleDivSolution/Circle.tsx
new file mode 100644
index 000000000..4befcab1c
--- /dev/null
+++ b/viz/exercise/AnimationSimpleDivSolution/Circle.tsx
@@ -0,0 +1,24 @@
+import { animated, useSpring } from 'react-spring';
+
+type CircleVizProps = {
+  position: number;
+  color: string;
+};
+
+export const Circle = ({ position, color }: CircleVizProps) => {
+  const springProps = useSpring({
+    to: { position, color },
+  });
+
+  return (
+    <animated.circle
+      strokeWidth={2}
+      fillOpacity={0.4}
+      r={38}
+      cy={50}
+      cx={springProps.position}
+      stroke={springProps.color}
+      fill={springProps.color}
+    />
+  );
+};
diff --git a/viz/exercise/AnimationSimpleDivSolution/Graph.tsx b/viz/exercise/AnimationSimpleDivSolution/Graph.tsx
new file mode 100644
index 000000000..a6ca75825
--- /dev/null
+++ b/viz/exercise/AnimationSimpleDivSolution/Graph.tsx
@@ -0,0 +1,33 @@
+import { useState } from 'react';
+import { animated, useSpring } from 'react-spring';
+
+const width = 500;
+const height = 300;
+
+export const Graph = () => {
+  const [position, setPosition] = useState(40);
+
+  const springProps = useSpring({
+    to: { left: position },
+  });
+
+  return (
+    <div
+      style={{ width, height, position: 'relative' }}
+      onClick={() => {
+        setPosition(position > 100 ? 40 : width - 50);
+      }}
+    >
+      <animated.div
+        style={{
+          left: springProps.left,
+          top: 50,
+          position: 'absolute',
+          width: 50,
+          height: 50,
+          backgroundColor: 'red',
+        }}
+      ></animated.div>
+    </div>
+  );
+};
diff --git a/viz/exercise/AnimationSimpleDivSolution/index.js b/viz/exercise/AnimationSimpleDivSolution/index.js
new file mode 100644
index 000000000..fa564d27f
--- /dev/null
+++ b/viz/exercise/AnimationSimpleDivSolution/index.js
@@ -0,0 +1,6 @@
+// File used to render something in codesandbox only
+import ReactDOM from 'react-dom';
+import { Graph } from './Graph';
+
+const rootElement = document.getElementById('root');
+ReactDOM.render(<Graph />, rootElement);
diff --git a/viz/exercise/AnimationSimpleDivSolution/package.json b/viz/exercise/AnimationSimpleDivSolution/package.json
new file mode 100644
index 000000000..df56d88f4
--- /dev/null
+++ b/viz/exercise/AnimationSimpleDivSolution/package.json
@@ -0,0 +1,31 @@
+{
+  "name": "pie-chart-basic",
+  "version": "1.0.0",
+  "description": "",
+  "keywords": [],
+  "main": "index.js",
+  "dependencies": {
+    "react": "17.0.2",
+    "d3": "7.1.1",
+    "react-dom": "17.0.2",
+    "react-scripts": "4.0.0",
+    "@react-spring/web": "^9.3.1",
+    "react-spring": "9.3.2"
+  },
+  "devDependencies": {
+    "@babel/runtime": "7.13.8",
+    "typescript": "4.1.3"
+  },
+  "scripts": {
+    "start": "react-scripts start",
+    "build": "react-scripts build",
+    "test": "react-scripts test --env=jsdom",
+    "eject": "react-scripts eject"
+  },
+  "browserslist": [
+    ">0.2%",
+    "not dead",
+    "not ie <= 11",
+    "not op_mini all"
+  ]
+}