Some have called yarn bombing a feminist response to graffiti. Meet the sisters behind one of San Francisco's most prominent displays.

Reported by Suzie Racho. Bay Curious is made by Olivia Allen-Price, Jessica Placzek, Paul Lancour, Ryan Levi and Suzie Racho. Additional support from Carly Severn, David Weir, Katie McMurran and Howard Gelman. Holly Kernan is Vice President for News. Theme music by Pat Mesiti-Miller. Ask us a question or sign up for our newsletter at BayCurious.org. Follow Olivia Allen-Price on Twitter @oallenprice.