Divers in Tulamben, Bali, may soon hardly recognize a place where beautiful corals cling to the seabed below, or even know how they got there.

But one Chinese female diver will always know, for she is the one who “planted” them there.

Standing silently under the water are 59 ceramic pillars with capitalized letters carved onto their tops, creating a crossword puzzle-like scene. The letters spell 13 words, such as “fighting,” “save,” “coral reef,” and “breath.” The name of the puzzle is also spelled out: YILI PUZZLE.

Peng Yili, the 23-year-old diver and the designer of the puzzle said she thought about the idea in November 2015 during a gap year in Tulamben, where she enrolled in a diving course.

“I was trying to put on sunblock cream, but was stopped by my instructor, who said it can harm ocean life. That is when the idea hit me. I wanted to set up an underwater art installation. YILI PUZZLE can’t protect ocean life, but it’s made of ceramic, which means coral reefs can grow on it. It's like a shelter or manmade rocks,” Peng told People’s Daily Online.

By June the next year, the installation was set up underwater. It took Peng seven months to complete her project. Peng said the entire process was complicated, from applying for permits with local authorities to the design and production of the ceramic pillars.

“I was particularly careful with the packaging to make sure all remained intact. Generally, polyfoam is used, which is light and cheap, but this material also causes pollution. So I chose high-temperature foam board insulation instead, which won’t float away easily and cause pollution. They’re also useful for local construction work,” Peng explained.

Her decision doubled the packaging costs, and all the materials turned out to be high-demand, hard-to-get products in Bali. But local residents offered her as much help as possible during the project's installation.

Peng joked that her project came under pressure from her university, as she had to return to the School of the Art Institute of Chicago by August. She also admitted that her YILI PUZZLE was not cheap, about the same price as her annual tuition. While her family supported her idea, she received no direct financial support from them. She also did not try to find a sponsor, in the hope that YILI PUZZLE would become a personal art piece instead of a commercial one.

According to Peng, some of the pillars have now been moved, making it harder to see the order of the letters. Life is starting to flourish on the pillars as well.

“As its designer, as soon as YILI PUZZLE was completed, it no longer belonged to me. It is a gift from me to the ocean. It’s up to Mother Nature now to decide its fate, be it a home for coral reefs or lost in sea. I don’t expect anyone to take care of it for me. It doesn’t matter if anyone should remember it. It’s for the coral reefs, not humans,” Peng said, adding that she may set up similar installations elsewhere in the future.

Most divers are aware that sunblock cream can harm ocean life. It’s also commonsense, Peng noted. “But it’s a personal choice in the end. A righteous person will be self-disciplined, and those people will naturally become more aware about the environment. Hopefully they'll have a positive influence on their friends,” she said.