Visitors to a new exhibit at the Museum of Chinese in America may find themselves scratching their heads over a series of tangrams, deceptively simple-looking puzzles that have been enthralling and confounding Westerners for almost two hundred years—and the Chinese for even longer than that.

A tangram is a square carved into seven pieces that can be rearranged to match any number of shapes or figures outlined on an accompanying diagram—bird, horse, sailboat…. Sound like fun? Get ready to kneel.  At the museum, oversized plastic tangrams are spread out on the floor like building blocks in a kindergarten classroom, proving an irresistible attraction to puzzle enthusiasts like Samuel Lee, age 3.

If you prefer to experience the museum in an upright position, or if a certain traumatic SAT-related memory still causes you to grow faint at the mere thought of anything involving spatial reasoning, there’s still plenty to enjoy in the exhibit.

Apart from several other hands-on stations, where the mathematically inclined can tackle sliding-block puzzles and interlocking-ring puzzles, there are dozens  of puzzle antiques, many of them so beautifully made as to charm even the most geometry-averse visitor.  Take, for example, the 19th-century stained-wood tangrams from Fujian Province, which double as tables.

The one-room exhibit represents just a small fraction of a 1,400-piece collection belonging to Peter Rasmussen and Wei Zhang, a husband-and-wife collector team from California.

As it happens, the story of how Rasmussen and Zhang started their collection has some of the key elements of a good puzzle: mystery, a protracted period of frustration, and a surprising resolution.  

In 1994, Zhang, who had just graduated from a master’s program in computer science, and Rasmussen, who owned a company that published math textbooks,  discovered a rare 1958 Chinese booklet on “ingenious ring puzzles”—interlocking wire shapes that, as Rasmussen put it recently, reward puzzlers who have “a knack for spatial relations.” Zhang, who remembered similar puzzles from her childhood in Xinjiang Province in the far northwest of China, was fascinated. She and Rasmussen wanted to find the man who made the specific puzzles illustrated in the booklet, but they didn’t know how to get in touch with him. He was credited merely as “an old craftsman named Ruan Liuqi who lives in Suzhou.”  

After several unsuccessful attempts to track down the book’s author, they visited Suzhou, where they rented bicycles and rode around the city, stopping elderly people on the street and asking if the name Ruan Liuqi rang any bells. When that failed, they looked through the records at the local police station.

It turned out that Ruan had died decades earlier but was survived by five sons and a daughter, who had helped their father make the puzzles, which he sold on the street.

Rasmussen and Zhang got in touch with some of Ruan’s offspring and learned that they had long since given up the craft—street businesses were discouraged during the Cultural Revolution. Inspired by Ras­mussen’s and Zhang’s interest, Ruan’s children dusted off their tools and taught the craft to their own children and grandchildren. Several family members now run successful puzzle shops in cities throughout China.  

Zhang and Rasmussen, meanwhile, acquired about 40 “ingenious rings” for themselves, a couple dozen of which can now be found in the museum.  

Since starting their collection, Rasmussen and Zhang have bought about 100 puzzles every year.

“Our goal is to help preserve one small aspect of Chinese culture,” Rasmussen said by phone from his home in California. “Society in China is changing so quickly right now that a lot of culture is being lost.”

He added that he and Zhang hope to ultimately take the collection back to China. “That’s where it came from, where it’s most appreciated,” he said. “That’s where it should have a home.”

For now, though, if you want see its highlights—or if you feel like testing your spatial-reasoning skills—you only need to travel to Chinatown.

Museum of Chinese in America is at 215 Centre St. It is open Monday and Friday 11 am–5 pm; Thursday 11 am–9 pm; Saturday and Sunday 10 am–5 pm. 212-619-4785, mocanyc.org. Admission: $7, $4 seniors and students.