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Building the Model

Step 1 Adding Box Variables

In this example, you will model the following situation: On a Monday, 100 students return to school, one of whom has the flu. As time passes, the sick student unwittingly infects his classmates, who in turn go on to infect others. This could be generalized as follows:

Over time, susceptible people get sick and become infected people.

To begin building the model, create two box variables: one for Susceptible People and one for Infected People. These will allow you to keep track of how many healthy and sick people there are.


  • ICON Click on the Box Variable button on the toolbar.
  • Now click in the workspace where you want to add a box variable.
  • A blank box will appear with a blinking cursor inside. Type in a name for the box variable and press enter.
  • By clicking again in the workspace, you can continue to add box variables until you select a different button from the toolbar.

Adding Box Variables

Adding Box Variables

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