Build a store using Legos or other toys, and control the number of people inside using robotics! First build the store, and set the WeDo 2.0 distance sensor in front of the door. Connect a motor that will show red and green signs depending on how much it turns (similar to the dog tail Scratch tutorial). This app detects customers entering and leaving a store. It turns the sign red when the maximum occupancy is reached (default to 2 people). An alarm sounds if people try to enter the store when it's already full. Have fun!