The black dots, representing a group of people, move at random on the green background. Each group has a 1% chance of dying out and 2% chance of creating a new group.

Sometimes the population dies out. If this happens, select the "group" icon in the Gallery, select the pencil in the Worksheet, and click anywhere on the green background. Each click creates a new black dot.

To start over, select on the hammer and click on a green square. All the dots should disappear. Then repeat 2.

What are the odds of a single group spawning a large population?

There is a problem with the program. When the population gets large, new groups are made outside the green area. They eventually migrate off the Worksheet and cause an error. This is fixed in Pop2.

You can change the growth and death rates by changing the numbers in the conditions that control the behavior of the groups. Do you see how to increase the growth rate? How about decreasing it?