Containers in Proto.io are both a fundamental building block, and key to achieving advanced prototypes. Aside from the standard scrollable vertical container and horizontal snap carousel containers, use them to convert asset layers into multiple states for animation. Convert interaction areas into a container to toggle states and fire other items events. Use containers as reusable symbols to repeat throughout your prototype where visual changes ripple throughout each instance. Even group each container instance with a different interaction area so they can interact independently. Achieve sophisticated auto-complete drop-down search areas. And more.