Kenton Smith had stumbled upon a relic of another era. The images, commonly known as silicon doodles, were used around the 1970s and after as a form of expression and to protect against technological theft. The doodles could be tame — the designer’s initials — or elaborate and whimsical, like a Tyrannosaurus rex driving a convertible.

Though well documented, the doodles are a rarity, and the practice has largely been phased out. The hunt for them requires time, money for parts and an archaeologist’s spirit as collectors search flea markets and online auctions for the chance to unscrew hardware casings, whittle down chip caps and train their eyes to catch a glimpse of magic.

“It blew me away,” said Mr. Smith, 36, who is from Madison, Wis. He now works in digital design, but from a young age he was interested in electronics and computers. He was especially drawn to the “hidden beauty” of integrated circuits, he said.

He once spotted the tiny image of a pyramid on a chip and shrugged it off as a simple marker, but the smiley face opened a flood of questions. Through his research, he discovered a Florida State University website, the Silicon Zoo, which in the 1990s began cataloging the images made by chip designers.

“There’s so many different things that designers have left behind to leave their mark, and they don’t display it,” Mr. Smith said. “It’s just sort of hidden there, and no one’s ever going to see it.”