Yoko Ono, Three Mounds and Skyladders, Three Mounds 1999-2008: Three piles of earth each 80cm high with signs on the floor, handwritten text in ink on paper., Skyladders: 29 Skyladders from Liverpool Biennial 2008; each donated ladder is accompanied by a hand written note and personal wishes from its contributor. courtesy BALTIC Centre for Contemporary Art, Copyright: Yoko Ono, Photographer: Colin Davison