This Applet calculates the Biblical male population of the earth if since the time Noah and the three other guys got off the Arc. It uses a 20 year generation and each guy reproduces himself four times. Nobody dies in this applet. It also uses Brother Herald Camping's theory that 6000 years have passed since that time. If the world population is 6 Billion (6.0E9) people (3 Billion men) it can be seen that Noah and friends could easily have repopulated the earth. The number should be in the grey box if you can run java applets.

import java.awt.*;
public class population extends java.applet.Applet{
double pop;
public void init(){
pop = 3;
for(int i = 1;i<300;i++){
pop = pop * 4;
}
}
public void paint(Graphics screen) {
screen.drawString("population = " + pop, 10, 10);
}
}