The design of the Liberty Bell established the basic principles that would characterize the slot machine genre for many years to come, laying the foundation for subsequent moind slots appdels. As the 20th century went on, slot machines changed. In the 1960s, electromechanical devices were introduced, enabling more intricate gameplay and the addition of lights and sounds to improve the gaming experience. A major turning point for slot machines occurred with the introduction of the internet in the latter half of the 20th century.