Travelers to the Tibet autonomous region often come across piles of stones inscribed with scriptures and Buddhist images.
These Mani stones are the work of Tibetan craftsmen such as Olo Tsering, who spends his days focused on meticulously carving a religious mantra on stacks of stone plates.
When Tibetan nomad Tashi Penpa commissioned the mantra Yikgya, Olo Tsering took four days to complete it.
The 46-year-old craftsman has spent 30 years working on religious carvings. He considers his skill to be a valuable gift to him from his ancestors, and he strives to pass it on.
In early March, Tibetans revel in celebrations to mark the Tibetan New Year Festival. Many temples welcome flocks of pilgrims during this time, and prayer-stone carvers see it as an opportunity to sell their work.
"As people get wealthier, the demand for prayer-stone carving is also increasing," Olo Tsering said.
He comes from the Yushu Tibetan autonomous prefecture in Qinghai province. Yushu boasts the world's largest prayer-stone pile of its kind, the Jana Mani Heap.
Olo Tsering headed to Tibet's regional capital of Lhasa two decades ago. He dabbled in various kinds of work before finally choosing to focus on prayer-stone carving.
His pieces include various Buddha images and Tibetan scriptures, such as the famous Om mani padme hum and the mantra of the bodhisattva of compassion, Avalokiteshvara, which are important parts of Tibetan culture.
"I am the third-generation prayer-stone carver in my family, and I hope this tradition will last forever," he said.
Olo Tsering said he has trained more than 10 apprentices, including his son.