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HTML

              
                <script language="javascript" type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.5.8/p5.js"></script>     

              
            
!

CSS

              
                body {margin:0px; padding:0px; overflow: hidden}
              
            
!

JS

              
                // Global variables to track frame initialization and the number of harmonic circles.
let prevInitFrame = 1;
let n = 1;
let baseRadius = 100;  // Initial circle's radius
let plotData = [];  // Data to be plotted on the graph

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

function draw() {
    clear();
    background(224, 239, 243);

    let x = 0, y = 0;

    // Setting up the central circle and base coordinates
    push();
    translate(baseRadius + 20, height / 2);
    fill(255); stroke(0); strokeWeight(1);
    ellipse(x, y, baseRadius * 2, baseRadius * 2);

    // Multiplier based on Fourier series coefficients for square waves
    let m = 4 / PI;

    // Drawing harmonic circles
    for (let i = 0; i < n; i++) {
        let d = 1 + i * 2;
        let rad = radians(frameCount - 1) * 2 * d;
        let radius = baseRadius / d * m;
        let sine = sin(rad);
        let cosine = cos(rad);
        let nx = x + cosine * radius;
        let ny = y - sine * radius;

        line(x, y, nx, ny);  // Line from one circle's perimeter to the next's
        drawCircleMarker(createVector(nx, ny), 2);  // Dot on the circle's perimeter

        // Update x and y for the next circle
        x = nx;
        y = ny;
    }

    // Drawing the main line and markers
    drawCircleMarker(createVector(0, 0), 2);  // Center of the main circle
    line(baseRadius + 20, y, -baseRadius - 20, y);  // Horizontal line
    drawCircleMarker(createVector(x, y), 4);  // Dot on the main line

    pop();

    // Adjusting graph width based on canvas size and circle size
    let graphW = width - (baseRadius + 20) * 2;
    let graphX = (baseRadius + 20) * 2;

    // Resetting data when reaching the end of the canvas
    if (frameCount > prevInitFrame + graphW) {
        plotData = [];
        prevInitFrame += graphW;
    }

    plotData.push({ x: frameCount - prevInitFrame, y: -y });

    // Increase harmonic circles every 90 frames, reset after reaching 40 circles
    if (frameCount % 90 == 0) {
        n++;
        if (n > 40) {
            n = 1;
        }
    }

    // Plotting the resulting wave
    plotGraph(plotData, graphX, height / 2, graphW, height - 64, 0, graphW, -height / 2 + 32, height / 2 - 32, "time", "y");

    // Displaying the number of harmonic circles
    drawLabel(8, height - 32, "n = " + n, LEFT);
}

function plotGraph(data, ox, oy, w, h, minX, maxX, minY, maxY, xLabel, yLabel) {
    let left = ox - minX / (maxX - minX) * w;
    let top = oy - maxY / (maxY - minY) * h;
    let labelLeft = abs(left - ox) > abs(left + w - ox);
    let labelTop = abs(top - oy) > abs(top + h - oy);

    push();

    // Drawing the graph axes
    noFill(); stroke(0);
    line(left, oy, left + w, oy);  // X-axis
    line(ox, top, ox, top + h);    // Y-axis

    // Plotting the wave data
    beginShape();
    for (let i = 0; i < data.length; i++) {
        let x = ox + data[i].x / (maxX - minX) * w;
        let y = oy - data[i].y / (maxY - minY) * h;
        vertex(x, y);
    }
    endShape();

    // Drawing graph labels
    fill(0);
    drawLabel(labelLeft ? left : left + w, oy + (labelTop ? 16 : -8), xLabel, labelLeft ? LEFT : RIGHT);
    drawLabel(ox, labelTop ? top : top + h, yLabel, labelLeft ? RIGHT : LEFT);

    pop();
}

function drawLabel(x, y, label, align = CENTER) {
    push();
    noStroke();  // Removes potential line strokes
    textFont("monospace");
    textSize(14);
    textAlign(align);
    // Adjusting position based on alignment for better visibility
    if (align == LEFT) x += 6;
    if (align == RIGHT) x -= 6;

    text(label, x, y);
    pop();
}

function drawCircleMarker(p, size) {
    ellipse(p.x, p.y, size * 2, size * 2);
}

              
            
!
999px

Console