On Sat., Dec. 13, as fiber artist Robyn Love, bottom right, watched, a team of professional riggers, erected her “water-tank cozy” on top of 395 Broadway, a block south of Canal St., in Tribeca. The crocheted, sweater-like sheath is meant to resemble a pencil. The work was commissioned by educational charity D&AD to promote its Pencil Awards, a graphic design and advertising prize. The riggers hauled a ladder up the side of the 15-story building to facilitate their installation, then draped and secured the cozy over the 10,000-gallon water tank. The cozy — knitted by Love and six volunteers — includes more than 30 miles worth of yarn.