diff --git a/package-lock.json b/package-lock.json
index f0344c5c4..5e6dfcf63 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -13966,8 +13966,7 @@
       "version": "5.3.2",
       "resolved": "https://registry.npmjs.org/acorn-jsx/-/acorn-jsx-5.3.2.tgz",
       "integrity": "sha512-rq9s+JNhf0IChjtDXxllJ7g41oZk5SlXtp0LHwyA5cejwn7vKmKp4pPri6YEePv2PU65sAsegbXtIinmDFDXgQ==",
-      "dev": true,
-      "requires": {}
+      "dev": true
     },
     "acorn-walk": {
       "version": "6.2.0",
diff --git a/src/components/Counter.js b/src/components/Counter.js
index 447a5e849..b1311e1b6 100644
--- a/src/components/Counter.js
+++ b/src/components/Counter.js
@@ -46,32 +46,40 @@ STEP 6:
   This click handler needs to use 'setCount' to set the 'count' to be zero again.
 */
 
-import React from 'react'; /* STEP 0 */
+import React, { useState } from 'react'; /* STEP 0 */
 
-export default function Counter() {
+export default function Counter(props) {
   /* STEP 1 */
-
+  const [count, setCount] = useState(0);
   const increment = () => {
-    /* STEP 4 */
+    setCount(count + 1);
   };
   const decrement = () => {
-    /* STEP 5 */
+    setCount(count - 1);
   };
   const reset = () => {
-    /* STEP 6 */
+    setCount(count - count)
   };
 
   const style = {
     fontSize: '1.5em',
     marginBottom: '0.3em',
-    color: 'royalblue', /* STEP 2 */
+    color: count % 2 === 0 ? "royalblue" : "crimson"
   };
 
+  function evenOdd(arg){
+    if (arg % 2 == 0) {
+      return "even";
+    } else {
+      return "odd";
+    }
+  }
+
   return (
     <div className='widget-counter container'>
       <h2>Counter</h2>
       <div id='count' style={style}>
-        Number 0 is even {/* STEP 3 */}
+        Number {count} is {evenOdd(count)}
       </div>
       <div>
         <button id='increment' onClick={increment}>Increment</button>
diff --git a/src/components/Input.js b/src/components/Input.js
index 36bf8fe03..53fa1dc92 100644
--- a/src/components/Input.js
+++ b/src/components/Input.js
@@ -34,34 +34,34 @@ STEP 6:
   We need to add an extra prop to the <input /> element like so: value={inputValue}
 */
 
-import React from 'react'; /* STEP 0 */
+import React, { useState } from 'react'; /* STEP 0 */
 
 export default function Input() {
   /* STEP 1 */
-
+  const [inputValue, setInputValue] = useState("");
   const changeInput = evt => {
     // When the input changes, its whole value can be found inside the event object.
     // Log out the synthetic event object 'evt' and see for yourself.
     const { value } = evt.target;
-
+    setInputValue(value);
     /* STEP 4 */
   };
   const reset = () => {
-    /* STEP 5 */
+    setInputValue("");
   };
 
   const style = {
     fontSize: '1.5em',
     marginBottom: '0.3em',
-    color: 'royalblue', /* STEP 2 */
+    color: inputValue.length <= 10 ? 'royalblue' : "crimson"
   };
 
   return (
     <div className='widget-input container'>
       <h2>Input</h2>
-      <div id='output' style={style}></div> {/* STEP 3 */}
+      <div id='output' style={style}>{inputValue.toUpperCase()}</div> {/* STEP 3 */}
       <div>
-        <input id='input' type='text' onChange={changeInput} /> {/* STEP 6 */}
+        <input id='input' type='text' onChange={changeInput} value={inputValue}/> {/* STEP 6 */}
         <button id='resetInput' onClick={reset}>Reset</button>
       </div>
     </div>
diff --git a/src/components/Moods.js b/src/components/Moods.js
index 98b49467f..11a7b4fef 100644
--- a/src/components/Moods.js
+++ b/src/components/Moods.js
@@ -28,35 +28,35 @@ STEPS 4, 5, 6:
   Inside these click handlers set the correct mood, using 'setMood' and the variables below the imports.
 */
 
-import React from 'react'; /* STEP 0 */
+import React, { useState } from 'react'; /* STEP 0 */
 
 const initialMood = 'Not sure how I feel';
 const happyMood = 'Quite happy!';
 const sadMood = 'Rather sad';
 
 export default function Moods() {
-  /* STEP 1 */
+  const [mood, setMood] = useState(initialMood);
 
   const makeHappy = () => {
-    /* STEP 4 */
+    setMood(happyMood);
   };
   const makeSad = () => {
-    /* STEP 5 */
+    setMood(sadMood);
   };
   const reset = () => {
-    /* STEP 6 */
+    setMood(initialMood);
   };
 
   const style = {
     fontSize: '1.5em',
     marginBottom: '0.3em',
-    color: 'crimson', /* STEP 2 */
+    color: mood === happyMood ? "royalblue":'crimson'
   };
 
   return (
     <div className='widget-moods container'>
       <h2>Moods</h2>
-      <div id='mood' style={style}>Not sure how I feel</div> {/* STEP 3 */}
+      <div id='mood' style={style}>{mood}</div> {/* STEP 3 */}
       <div>
         <button id='makeHappy' onClick={makeHappy}>Make Happy</button>
         <button id='makeSad' onClick={makeSad}>Make Sad</button>
diff --git a/src/components/Programmers.js b/src/components/Programmers.js
index bb4aee6bd..f2e4bfa9b 100644
--- a/src/components/Programmers.js
+++ b/src/components/Programmers.js
@@ -11,7 +11,7 @@ We can only feature one awesome programmer at a time.
 Find comments below to help you along.
 */
 
-import React from 'react';
+import React, { useState } from 'react';
 
 // Use this variable ONLY to initialize a slice of state!
 // There is something in the JSX right now breaking this rule...
@@ -28,6 +28,8 @@ export const listOfAwesome = [
 export default function Programmers() {
   // We'll have to use the state hook twice, as we need two slices of state.
   // The programmers list on the one hand, and the id of the featured programmer on the other.
+  const [programmers, setProgrammers] = useState(listOfAwesome);
+  const [featured, setFeatured] = useState(null);
 
   const getNameOfFeatured = () => {
     // Leave this for last!
@@ -35,12 +37,17 @@ export default function Programmers() {
     // It's going to utilize both slices of state to return the _name_ of the featured dev.
     // The beauty of closures is that we can "see" both slices of state from this region
     // of the program, without needing to inject the information through arguments.
+    for (let i = 0; i < programmers.length; i++){
+      if (programmers[i].id === featured){
+        return programmers[i].name;
+      }
+    }
   };
 
   const style = {
     fontSize: '1.5em',
     marginTop: '0.5em',
-    color: 'royalblue', // 🤔 color turns to gold, when celebrating
+    color: featured ? "gold" : 'royalblue', // 🤔 color turns to gold, when celebrating
   };
 
   return (
@@ -51,9 +58,9 @@ export default function Programmers() {
           /* Nasty bug! We should map over a slice of state, instead of 'listOfAwesome'.
           We might think: "it works, though!" But if the list of programmers is not state,
           we could never add or edit programmers in the future. The list would be a static thing." */
-          listOfAwesome.map(dev =>
+          programmers.map(dev =>
             <div className='programmer' key={dev.id}>
-              {dev.name} <button onClick={() => { /* in here set the featured id to be dev.id */ }}>Feature</button>
+              {dev.name} <button onClick={() => { setFeatured(dev.id)}}>Feature</button>
             </div>
           )
         }
@@ -63,7 +70,7 @@ export default function Programmers() {
           // Ternaries are fantastic to render "one thing or the other" depending on the "truthiness" of something.
           // Pseudo-code: if the currently featured id is truthy render text 1, otherwise render text 2.
           // Replace the hard-coded false with the correct variable.
-          false
+          featured
             ? `🎉 Let's celebrate ${getNameOfFeatured()}! 🥳`
             : 'Pick an awesome programmer'
         }
diff --git a/src/components/Spinner.js b/src/components/Spinner.js
index d0326fd34..5a92d9cca 100644
--- a/src/components/Spinner.js
+++ b/src/components/Spinner.js
@@ -37,23 +37,26 @@ STEP 4:
   Do you remember the operator we use to do "not"?
 */
 
-import React from 'react'; /* STEP 0 */
+import React, { useState } from 'react'; /* STEP 0 */
 
 export default function Spinner() {
 /* STEP 1 */
+const [spinnerOn, setSpinnerOn] = useState(true);
+
 
   const toggleSpinner = () => {
   /* STEP 4 */
+  setSpinnerOn(!spinnerOn);
   };
 
   return (
     <div className='widget-spinner container'>
       <h2>Spinner</h2>
       {
-        true && <div id='spinner' className='spinner'>--+--</div> /* STEP 2 */
+        spinnerOn && <div id='spinner' className='spinner'>--+--</div> /* STEP 2 */
       }
       <button id='toggleSpinner' onClick={toggleSpinner}>
-        Hide Spinner {/* STEP 3 */}
+       {spinnerOn ? "Hide" : "Show"} Spinner
       </button>
     </div>
   );
diff --git a/src/components/Squares.js b/src/components/Squares.js
index 25ab72546..dfbbdb246 100644
--- a/src/components/Squares.js
+++ b/src/components/Squares.js
@@ -14,7 +14,7 @@ Only one square (or none) can be active at any given point.
 Find comments below to help you along.
 */
 
-import React from 'react';
+import React, { useCallback, useState } from 'react';
 
 // Use this variable ONLY to initialize a slice of state!
 const listOfSquareIds = ['sqA', 'sqB', 'sqC', 'sqD'];
@@ -24,13 +24,15 @@ export default function Squares() {
   // 'activeSquare'. One holds the _array_ of square ids, and the other keeps track
   // of the currently active square. On page load there's no active square,
   // so the value of 'activeSquare' should be null.
+  const [squares, setSquares] = useState(listOfSquareIds);
+  const [activeSquares, setActiveSquares] = useState(null);
 
   const getClassName = id => {
     // This is NOT a click handler but a helper, used inside the JSX (see below).
     // It should return a string containing the class name of 'active', if the id passed
     // as the argument matches the active square in state, empty string otherwise.
     // Right-click and "inspect element" on the square to see its effect.
-    return ''
+    return (activeSquares === id ? "active" : "");
   };
 
   const markActive = id => {
@@ -38,6 +40,13 @@ export default function Squares() {
     // Set the id argument to become the active id in state
     // (unless it already is, in which case we should reset
     // the currently active square id back to initial state).
+    for (let i = 0; i < squares.length; i++) {
+      if (activeSquares){
+        setActiveSquares(null);
+      } else {
+        setActiveSquares(id);
+      }
+    }
   };
 
   return (
@@ -48,7 +57,7 @@ export default function Squares() {
           // Nasty bug! We should map over a slice of state, instead of 'listOfSquareIds'.
           // We might say: "it works, though!" But if the list of squares is not state,
           // we could never add squares, change squares or remove squares in the future. Fix!
-          listOfSquareIds.map(id =>
+          squares.map(id =>
             <div
               id={id}
               key={id}