Mark Chester often puzzled his friends and family because they couldn't understand why he never got a "normal" nine-to-five job.

But no one seems baffled now, for his experiences as a freelance photographer — including for the Jewish Bulletin — led him into developing Rex Games, a million-dollar firm that produces puzzles.

"Life is a colorful puzzle where scattered events somehow and eventually fit together," said Chester, a self-proclaimed "wandering Jew" who founded the San Francisco-based company.

Now that Chester's life is finally pieced together, his games are selling everywhere. They're being used as corporate training tools by groups as diverse as the FBI, American Express, Chevron and the Internal Revenue Service.

Chester's games are designed to foster analytical thinking. Targeted at children ages 5 and up, the games include "Word Trek," which develops vocabulary and spelling skills, and "3-spot," a tic-tac-toe-like strategy game with the complexity of chess.

One of his best-selling games, "Tangoes," is based on how ancient Chinese scholars developed their students' thinking skills. In Tangoes, the object is to recreate specific shapes by using seven geometric puzzle pieces.

Although the game derives from more Confucian than Maimonidian thought, Chester said his brain-teasers have a Jewish appeal.

"It's part of the Jewish heritage that we accept life's challenges, that we try to make things work," said the 52-year-old Mill Valley resident. "My father was that kind of man. He had a hard work ethic, was from Russia and instilled in me to work honestly, have integrity and to be imaginative."

But before Rex Games flourished, Chester had to convince store owners to sell his game. In order to do this, he figured out a way to apply his skills as a freelance photojournalist to running a business.

"It was an easy transition," he said. "Being a freelance photographer teaches you how to promote, how to be a business person, how to establish rapport with people and how to sell."

Sometimes, however, developing a successful marketing strategy was almost as frustrating as one of Chester's puzzles.

"If the buyer rejected the project, I just moved on," Chester said. "I became thick-skinned and resilient, and it prepared me to run a business."

Chester, whose business has been running since 1988, said he believes his Jewish heritage has given him the strength to persevere.

"Perseverance is part of our heritage. When you believe in something you don't give up," he said. "I didn't give up on making the game popular and successful — I believed in the game [and] I was enthusiastic. I can't sell anything I don't believe in."

Chester said his games, which are being used in mainstream and special education schools, have been recognized as educational tools by such groups as the National Council of Teachers of Mathematics, National Association for Gifted Children and the Parents' Choice Foundation.

He also said his games offer a sound choice for parents looking for alternatives to video games. His games "are affordable, inexpensive, non-electronic, compact, easy to take on vacations, can develop thinking skills and problem-thinking skills."

As Chester's company continues to grow, he intends to hold to his belief that the development of one's thinking and learning skills should be a fun process, just like life itself.

"Life is a continual exercise of fitting pieces together, and with age and wisdom, it's easier to understand one's own puzzle."