Eastsound trees have lately sprouted a smattering of colorful, trunk-warming sweaters. It’s a mystery who’s behind the cheerful smockery, but the pranks may be an offshoot of an international “yarn bombing” movement by the knit graffiti group Knitta Please, founded by Texas textile artist Magda Sayeg. June 11 has been designated as “International Yarn Bombing Day.”

Participants strike quickly, decorating public places with knitted covers for random items: light poles, bus seats, bridge railings – you name it.

There’s also a knitting group called “Graffiti Grannies” on Facebook. Self-described “middle-aged granny urban woolerists,” their tagline is this: “You won’t see us or hear us, but you will know we have been there!”