One of the greatest VR puzzles ever
Interactivity is a common feature in immersive experiences, though it does not need to be complex to be engaging. An early example is the Mimetic Starfish which featured in the Mind Zone of the Millennium Dome exhibition. The starfish interacted in a life-like manner with attendees, reaching out a tentacle towards their hands and jumping back if they moved too quickly.
Attendees were surprised and delighted by the Mimetic Starfish; an example of immersive technologies that resonates over two decades later.