Meditation doesn't necessarily mean inactivity. A simple feature such as this meditation walk is a garden focal point and a way to focus your thoughts. Note how the size of the stones goes from small to large as you move to the inside of the circle.
"Bamboo spiral: This gives an unusual auditory experience to anyone who ventures into the ‘forest’ of hanging bamboo poles - a version of surround sound!" - Sounds and Senses ≈≈ it's like an enormous wind chime.