By Mike DeNardo

PHILADELPHIA (CBS) — It might be hard to buy pink yarn these days, because women are knitting hats to wear to a National March on Washington.

Thousands of women plan to march on the National Mall, the day after Donald Trump is inaugurated. And many of them will be wearing hand-knitted pink hats they call “pussyhats.”

They look like pussycats, with two ears on top. The reference to Trump’s infamous remark is intentional, said Lisa Johnson who owns Hidden River Yarns in Manayunk.

“It kind of became a symbol, a power symbol for the women going to the march.”

With group knitting sessions taking place in the city, she said it’s been difficult, keeping pink yarn on the shelves.

“I had a great stock at the beginning of the week, but for my second time I’m starting to run out of pink yarn!”

Johnson said a sea of pink hats in Washington would be a visual statement for women’s rights.