The first thing you noticed about Laverne DeFazio was her initial. Half of the blue-collar duo on ABC’s “Laverne & Shirley,” she wore it on her sweaters, on her bathrobe, even on her work uniform at the Shotz Brewery. A loop up, a swoop down, and a kick outward, that stylized “L” announced that whatever circumstance Laverne might end up in, she couldn’t help but be herself.

The next thing you noticed was her voice, which Penny Marshall, who died Monday at age 75, gifted her. It was, reviewers always noted, nasal and boisterous, but it could also be wheedling, teasing, sarcastic or playful. Marshall played a whole repertoire on that brass instrument.

[Watch some Penny Marshall movie and TV moments.]

“Laverne & Shirley” was a spinoff of “Happy Days,” that 1970s trove of 1950s nostalgia. But though it was set in the same time period, it felt more of its current moment than its parent show. It focused not on Ike-era teens but a pair of young single women, living in a basement apartment, holding down factory jobs and, as the theme song said, “doing it our way.” (The opening credits scene of the pair standing on the bottling line, staring dreamily into space, remains one of the most poetic images in sitcomdom.)

The series began in 1976, quickly becoming a top-10 hit, then leapfrogging past “Happy Days” to take the No. 1 spot in the Nielsen ratings two seasons in a row. Part of its appeal was the same mix of nostalgia, slapstick and wacky characters, but it added a feisty, pop-feminist rebelliousness from the get-go: two best friends, dancing down a sidewalk, singing nonsense (“Schlemiel! Schlimazel! Hasenpfeffer Incorporated!”), sufficient on their own.