SOURCE

let mobileCheck = new MobileDetect(window.navigator.userAgent).mobile() !== null;

let count = mobileCheck ? 300 : 1000;
let r = mobileCheck ? 100 : 200;
let particles = [];

let influences = { // Multipliers
		mouse: 0.008,
		particles: 0.0025,
		center: 0.006,
		noise: 3
	};
let friction = 0.96;

let canvas, ctx;
let mouseIn = false;

let pos, acc, vel;

function setup() {
	canvas = createCanvas(windowWidth, windowHeight);
	ctx = canvas.drawingContext;
	canvas.canvas.onmouseenter = () => mouseIn = true;
	canvas.canvas.onmouseleave = () => mouseIn = false;
	
	randomizeParticles();
	
	pos = createVector(width / 2, height / 2);
	acc = createVector(0, 0);
	vel = createVector(0, 0);
}

function randomizeParticles() {
	particles = [];
	let r_ = r / 2;
	for(let i = 0; i < count; i++) {
		let p = createVector(
				random(-r_, width + r_),
				random(-r_, height + r_)
			);
		particles.push(p);
	}
}

function draw() {
	background(0);
	
	stroke(255);
	noFill();
	
	let center = createVector(width / 2, height / 2);
	let mouse = createVector(mouseX, mouseY);
	
	strokeWeight(1);
	
	// Influences:
	
	// Prevent the particles from taking too long, makes performance better
	// on mobile somewhat.
	let particleStart = performance.now();
	let maxTime = 10; // ms
	
	// By particles
	particles.some(n => {
		if(performance.now() - particleStart > maxTime) {
			return true;
		}
		
		let di = p5.Vector.sub(n, pos);//pos.dist(n);
		let d = di.mag();
		let inRegion = d < r;
		
		if(inRegion) {
			// Overpowered stroke color;
			stroke((1 - d / r) * (255 * 3));
			line(n.x, n.y, pos.x, pos.y);
			ellipse(n.x, n.y, (1 - d / r) * (r / 4));
			acc.add(di);
		}
	});
	acc.mult(influences.particles);
	
	// By center
	acc.add(p5.Vector.sub(center, pos).mult(influences.center));
	
	// By mouse
	if(mouseIn) {
		acc.add(p5.Vector.sub(mouse, pos).mult(influences.mouse));
	}
	else {
		let ns = noise(pos.x / 100, pos.y / 100, frameCount / 300);
		let ang = map(ns, 0.28, 0.72, 0, TAU);
		let v = p5.Vector.fromAngle(ang);
		acc.add(v.mult(influences.noise));
	}
	
	vel.add(acc);
	vel.mult(0.96);
	acc.set(0, 0);
	pos.add(vel);
	
	let dir = p5.Vector.add(pos, p5.Vector.mult(vel, r / 4));
	strokeWeight(4);
	stroke(255, 0, 0, 100);
	line(pos.x, pos.y, dir.x, dir.y);
}

function windowResized() {
	resizeCanvas(windowWidth, windowHeight);
}

function mousePressed() {
	noiseSeed(random());
	randomizeParticles();
}

function mouseWheel(e) {
	r += e.delta > 0 ? -10 : 10;
	r = max(30, min(min(width, height) / 3 * 2, r));
}

<div id="controls">
    <ul>
        <li>鼠标: 有影响</li>
        <li>点击: 随机化位置</li>
        <li>鼠标滚轮: 改变蜘蛛机器人半径</li>
    </ul>
</div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/mobile-detect/1.3.5/mobile-detect.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.5.6/p5.min.js"></script>

html,
body {
    background: black;
    margin: 0;
    overflow: hidden;
    color: white;
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}
#controls {
    font-family: sans-serif;
    position: absolute;
    top: 20px;
    left: 20px;
    pointer-events: none;
}