Beginner tutorial: Smooth variable changes (lerp, damping, easing)

Hi! I think a lot of beginners would appreciate a simple tutorial on using the lerp() function to achieve smooth motion and value changes.

I think something like this example would be pretty good:

```javascript
let rndBg = 0;
let newRndBg = 0;

let ellipseCol = 0;
let newEllipseCol = 0;

let d = 100;
let newD = 100;

let x = 0;
let y = 0;

let bigCircle = false;

function lerpVariables() {
rndBg = lerp(rndBg, newRndBg, 0.05);
ellipseCol = lerp(ellipseCol, newEllipseCol, 0.05);
x = lerp(x, mouseX, 0.05);
y = lerp(y, mouseY, 0.05);
d = lerp(d, newD, 0.05);
}

function setup() {
createCanvas(windowWidth, windowHeight);
colorMode(HSL);
}

function draw() {
lerpVariables();

background(rndBg, 50, 30);
fill(ellipseCol, 50, 70);
ellipse(x, y, d);
}

function mousePressed() {
bigCircle = !bigCircle;
bigCircle ? newD = 300 : newD = 50;
newRndBg = random(360);
newEllipseCol = random(360);
}
```

No target file or test is named. Start from the proposed JavaScript example and define the tutorial around lerp(), smooth motion, value changes, damping, and easing; it is done when the beginner-focused tutorial explains and demonstrates those topics.

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