Chaz Mason, right, attended the march with his 12-year-old daughter Fiona, left, who wants to be a neurosurgeon.

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Many refer to the crocheted hats as "thinking caps"

The hats are mostly in pink or gray

Washington CNN  — 

Pink and gray brain hats dotted the crowds at the March on Science in Washington, becoming one of the symbols of the march’s message.

Many referred to the crocheted hats as “thinking caps,” saying the headgear represents critical thinking, a cornerstone of science.

“People don’t look at both sides of an issue. We have the Trump administration, which runs on a lack of critical thinking,” said critical care nurse Craig Wright from Gainesville, Florida.

He and his wife each wore a brain hat, his in gray and hers in pink. Both were bought on Etsy.

Craig and Joni Wright from Gainseville, Florida, attended the Washington march donning their thinking caps.

Sherry Annee, who just marked 25 years as a science teacher, decked out her brain hat with messages related to education, like the elements of the periodic table spelling out her school: B-Re-Be-U-F. (That’s boron, rhenium, beryllium, uranium and fluorine to you non-scientists.)

The hats were also ripe for jokes: “We are brain friends, a brain trust,” joked a father with his daughter and a friend.

The crocheted caps gave a hat tip back to the ubiquitous bright-pink “pussyhats” that inundated Washington for the Women’s March in January. The knit caps with cat-like “ears” were symbols of resistance born out of a grassroots effort to flood the National Mall with a show of support for women’s rights.

Some pussyhats made an appearance at the March for Science, but in all sorts of colors, from the original pink to black, blue and green.

“It’s become a symbol,” said Beth Nolley, from Fairfax, Virginia. “I didn’t think it would be relevant beyond (the Women’s March), but it still is. For anything where people come together for a cause, it seems relevant to wear.”

Nolley said she crocheted 40 pussyhats for the Women’s March, but this time she crocheted a few more for the March for Science.

“We wanted it to be more earthy, so we added some color to ours and I made my friend’s green one there,” she said.

After all, it is Earth Day.