docs: public static Polygon newRandom(final int length, final Random random) {
  		require.positive(length);
  		final Polygon p = new Polygon(length);
  
  		p._data[0] = random.nextFloat(); // r
  		p._data[1] = random.nextFloat(); // g
  		p._data[2] = random.nextFloat(); // b
  		p._data[3] = max(0.2F, random.nextFloat()*random.nextFloat()); // a
  
  		float px = 0.5F;
  		float py = 0.5F;
  		for (int k = 0; k < length; k++) {
  			p._data[4 + 2*k] = px = clamp(px + random.nextFloat() - 0.5F);
  			p._data[5 + 2*k] = py = clamp(py + random.nextFloat() - 0.5F);
  		}
  		return p;
  	}