private static void createAndShowGUI(int nbugs) {
JFrame f = new JFrame("Swarm Demo");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
double dt = 0.01;
int ddt = 20;
if (nbugs > 20) {
dt = 0.1;
ddt = 2;
}
Playfield p = new Playfield(nbugs, dt, ddt);
f.add(p);
f.pack();
f.setVisible(true);
p.start();
}