The proliferation of Comic Sans is something of a fluke. In 1994, Mr. Connare was working on a team at Microsoft creating software that consumers eventually would use on home PCs. His designer’s sensibilities were shocked, he says, when, one afternoon, he opened a test version of a program called Microsoft Bob for children and new computer users. The welcome screen showed a cartoon dog named Rover speaking in a text bubble. The message appeared in the ever-so-sedate Times New Roman font.

Mr. Connare says he pulled out the two comic books he had in his office, "The Dark Knight Returns" and "Watchmen," and got to work, inspired by the lettering and using his mouse to draw on a computer screen. Within a week, he had designed his legacy.

A product manager recognized the font’s appeal and included it as a standard typeface in the operating system for Microsoft Windows. As home computers became widespread, Comic Sans took on a goofy life of its own.

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