diff --git a/src/components/Counter.js b/src/components/Counter.js
index 447a5e849..f36776316 100644
--- a/src/components/Counter.js
+++ b/src/components/Counter.js
@@ -18,19 +18,9 @@ The other things can simply be _derived_ from the count itself.
 STEP 0:
   Start by studying the component below, and importing the state hook.
 
-STEP 1:
-  Using the state hook, create a 'count', 'setCount' pair.
-  The 'count' state should be initialized to the number zero.
 
-STEP 2:
-  The 'style' object has the 'color' property hard-coded to "royalblue".
-  What the value of 'color' should be instead is a ternary expression that goes like this:
-  If count is even, then "royalblue", else "crimson".
 
-STEP 3:
-  We need to replace some hard-coded info in the JSX with expressions, interpolated inside curly brackets.
-  Start by replacing the character "0" with {count}. The 'count' slice of state is the source of truth here.
-  Then, replace the word "even" with a ternary: {if count is even number, then string "even", else string "odd"}.
+
 
 STEP 4:
   This click handler needs to use 'setCount' to schedule the 'count' to become the current 'count' plus one.
@@ -46,32 +36,51 @@ 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() {
-  /* STEP 1 */
+  // STEP 1:
+  // Using the state hook, create a 'count', 'setCount' pair.
+  // The 'count' state should be initialized to the number zero.
 
+  const [count, setCount] = useState(0);
+  
   const increment = () => {
-    /* STEP 4 */
+    setCount(count + 1);
   };
   const decrement = () => {
-    /* STEP 5 */
+    setCount(count -1);
   };
   const reset = () => {
-    /* STEP 6 */
+    setCount(0);
   };
 
+function isEven(num) {
+  return num % 2;
+};
+
   const style = {
     fontSize: '1.5em',
     marginBottom: '0.3em',
-    color: 'royalblue', /* STEP 2 */
+    color: isEven(count) ? 'crimson' : 'royalblue', 
   };
 
+    /* STEP 2:
+    The 'style' object has the 'color' property hard-coded to "royalblue".
+    What the value of 'color' should be instead is a ternary expression that goes like this:
+    If count is even, then "royalblue", else "crimson".
+  */
+  
+    // STEP 3:
+    // We need to replace some hard-coded info in the JSX with expressions, interpolated inside curly brackets.
+    // Start by replacing the character "0" with {count}. The 'count' slice of state is the source of truth here.
+    // Then, replace the word "even" with a ternary: {if count is even number, then string "even", else string "odd"}.
+  
   return (
     <div className='widget-counter container'>
       <h2>Counter</h2>
       <div id='count' style={style}>
-        Number 0 is even {/* STEP 3 */}
+        Number {count} is {isEven(count) ? 'odd' : 'even'}
       </div>
       <div>
         <button id='increment' onClick={increment}>Increment</button>
diff --git a/src/components/Input.js b/src/components/Input.js
index 36bf8fe03..7ccc21c96 100644
--- a/src/components/Input.js
+++ b/src/components/Input.js
@@ -34,34 +34,36 @@ 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 ? 'crimson' : 'royalblue' /* STEP 2 */
   };
 
   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' value = {inputValue} onChange={changeInput} /> {/* 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..69945ee43 100644
--- a/src/components/Moods.js
+++ b/src/components/Moods.js
@@ -28,7 +28,7 @@ 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!';
@@ -36,27 +36,27 @@ 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'/* STEP 2 */
   };
 
   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 e34c4f392..7c975003d 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...
@@ -23,23 +23,26 @@ export const listOfAwesome = [
   { id: '5', name: 'Frances Allen' },
   { id: '6', name: 'Carol Shaw' },
 ];
-
 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 [programmerId, setProgrammerId] = useState(null);
+    
   const getNameOfFeatured = () => {
     // Leave this for last!
     // This is NOT an event handler but a helper function. See its usage inside the JSX.
     // 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.
+    return programmers[programmerId-1].name;
+    
   };
 
   const style = {
     fontSize: '1.5em',
     marginTop: '0.5em',
-    color: 'royalblue', // 🤔 color turns to gold, when celebrating
+    color: programmerId ? "gold" : 'royalblue', // 🤔 color turns to gold, when celebrating
   };
 
   return (
@@ -47,12 +50,11 @@ export default function Programmers() {
       <h2>Programmers</h2>
       <div className='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={() => {
+                setProgrammerId(dev.id);
+              }}>Feature</button>
             </div>
           )
         }
@@ -62,7 +64,7 @@ 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
+          programmerId
             ? `🎉 Let's celebrate ${getNameOfFeatured()}! 🥳`
             : 'Pick an awesome programmer'
         }
diff --git a/src/components/Spinner.js b/src/components/Spinner.js
index d0326fd34..08973d3e5 100644
--- a/src/components/Spinner.js
+++ b/src/components/Spinner.js
@@ -37,23 +37,24 @@ 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 */
+    spinnerOn === false ? setSpinnerOn(true) : setSpinnerOn(false);
+     
   };
-
+    const spinnerText = spinnerOn===true ? 'Hide' : 'Show';
   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 */}
+        {spinnerText} Spinner {/* STEP 3 */}
       </button>
     </div>
   );
diff --git a/src/components/Squares.js b/src/components/Squares.js
index 25ab72546..f29060264 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, {useState} from 'react';
 
 // Use this variable ONLY to initialize a slice of state!
 const listOfSquareIds = ['sqA', 'sqB', 'sqC', 'sqD'];
@@ -24,20 +24,26 @@ 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 [activeSquare, setActiveSquare] = 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 id === activeSquare ? 'active' : '';
   };
 
+
   const markActive = id => {
     // This is a helper used inside an _inlined_ click handler (see below).
     // 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).
+    return activeSquare === id ? setActiveSquare(null) : setActiveSquare(id) ;
   };
 
   return (
@@ -48,7 +54,7 @@ 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}