Kaleidoscopic Neon Tunnel

// Kaleidoscopic Neon Tunnel (geometry)
ctx.fillStyle = 'rgba(6, 8, 12, 0.18)';
ctx.fillRect(0, 0, width, height);

const cx = width * 0.5;
const cy = height * 0.5;
const maxR = Math.min(width, height) * 0.38;
const t = time * 1.2;

ctx.beginPath();
const steps = 360;
for (let i = 0; i <= steps; i++) {
  const phi = (i / steps) * Math.PI * 2;
  const r = maxR * (0.6 + 0.3 * Math.sin(phi * 6 + t * 2) * Math.cos(phi * 4 - t));
  const px = cx + Math.cos(phi) * r;
  const py = cy + Math.sin(phi) * r;
  if (i === 0) ctx.moveTo(px, py);
  else ctx.lineTo(px, py);
}
ctx.closePath();
ctx.strokeStyle = 'hsla(' + ((time * 30 + 195) % 360) + ', 95%, 68%, 0.85)';
ctx.lineWidth = 2.2;
ctx.stroke();