This lecture introduces the concept of a state machine using a practical example with a robot named Thymio. The instructor challenges the audience to program Thymio to move forward when a specific button is pressed and stop when another button is pressed. Through interactive exercises, the audience learns about defining clear orders for the robot to follow based on its current state, such as sitting or standing. The lecture emphasizes the importance of clarity in defining actions for the robot to execute, ensuring it responds appropriately to different inputs.