What you’re looking at are Tibetan prayer wheels in motion, and they are deliberately set in motion as people walk past them. The practice is to spin the wheels and recite a mantra. It’s an ancient religious and meditative practice.
Prayer Wheels have been made for centuries in Tibet. They come in a range of sizes and styles, from little hand-held and table-top versions for sale in markets, way on up to giant 8-12 foot tall (5-6 feet diameter) versions like this one at Jokang Temple (for scale, note the monk in the bottom right corner).
Often built around Buddhist Stupas and Monasteries, you will find long rows of prayer wheels which people will spin as they walk clockwise around the building reciting mantras. The six syllable mantra Om Mani Padme Hum is most often recited. Tibetan people believe that the prayer wheel practice is a simple but profound way to develop compassion and wisdom. Buddhist teachers and ancient texts refer to the benefits of the Prayer Wheel for its ability to quickly harmonize the environment, increase compassion, encourage a peaceful state of mind, and assist practitioners on their journeys to enlightenment.
This is no fad. It is a practice grounded by well over a thousand years of rehearsal. When they are not in motion you can see the beautiful Sanskrit decoration of the wheels. Location: Sayme Monestary & Jokhang Temple, Tibet