How to Use the Interactive Figure

• Set a starting position for each runner by dragging his or her icon along the tracks.
  
  
• Change the direction the runner faces by clicking once on the runner's icon.
  
  
• Set a step size for each runner by clicking on the Arrow Up or Arrow Down buttons in the lower left.
  
  
• Click on an icon for either runner in the lower left to turn it on/off.
  
  

  	Play. Runs the simulation from current position.
  	Pause. Press Play to resume.
  	Reset. Returns runners to their previous positions.