Janet Napoli­tano, former US home­land secu­rity sec­re­tary, urged North­eastern University’s 2014 grad­u­ating class Friday not to fear life’s “zigs and zags.”

Beware the tyranny of the straight line,” she repeated during her keynote speech at the school’s 112th com­mence­ment inside TD Garden in Boston Friday, this spring’s first local col­lege graduation.

Using sail­boats as a metaphor, she explained to the 3,520 grad­u­ates: “Sail­boats do not glide through the water in a straight line. They tack. They zig-​​zag from here to there. That’s how they move forward.”

When the grad­u­ates return for their 50th reunion, she said, “my hope for you is that you will look back on the decades that have passed and see the twists and turns, the tacking, that are the hall­mark of a well-​​lived life,” said Napoli­tano, who became pres­i­dent of the Uni­ver­sity of Cal­i­fornia system in the fall.

Grad­u­ates wearing the stan­dard black robes and mor­tar­boards typed on smart­phones, undoubt­edly sending texts and tweets, and snapped photos of each other, them­selves, and the packed arena. As groups of stu­dents shuf­fled to the stage, other Huskies batted around beach balls.

An esti­mated crowd of 20,000-plus — including family, fac­ulty, and admin­is­tra­tors — looked on, cheering fre­quently and waving to grad­u­ates below. Video of the event streamed on the arena’s Jumbotron.

Napoli­tano, the former gov­ernor and attorney gen­eral of Ari­zona, became the third home­land secu­rity sec­re­tary and the first woman to hold the job when Pres­i­dent Obama appointed her in 2009. She led the Cab­inet agency, which was cre­ated after 9/​11, until 2013.

Read the article at The Boston Globe →