4th Ave Yarn Collective is a community knitting and crochet group centered on the Old Stone House in the Gowanus/Park Slope area of Brooklyn. Working with the Old Stone House, Arts Gowanus, and other local partners, members gather over the course of a year to hand-craft a large collaborative yarn mural, sometimes described as a yarn bomb, for installation on a neighborhood fence. The finished piece is unveiled during Gowanus Open Studios weekend, and the collective also produces smaller crocheted works for community events such as the Gowanus Art Parade.