Scissors.

From artist Beili Liu's The Mending Project (2011): “…Hundreds of Chinese scissors suspended from the ceiling in a shimmery cloud. The piece involved the artist sitting at a small black table, hand-mending patches of fabric together which visitors were encouraged to cut themselves near the entrance. As the performance continued, the piece grew as one continuous cloth and lay spread on the floor. The hovering mass of the downward-pointed scissors represent the distant fear and looming violence present in today’s cultural climate. The sharp blades above the artist are put in contrast by the silent and simple act of mending. The dichotomous result of the instant fear superimposed with the calming effect of the sewing created a surreal atmosphere in the room.” See more here.