The materials used in Andy Goldsworthy's art often include brightly coloured flowers, icicles, leaves, mud, pinecones, snow, stone, twigs, and thorns. He has been quoted as saying, "I think it's incredibly brave to be working with flowers and leaves and petals. But I have to: I can't edit the materials I work with. My remit is to work with nature as a whole." Goldsworthy is generally considered the founder of modern rock balancing. For his ephemeral works, Goldsworthy often uses only his bare hands, teeth, and found tools to prepare and arrange the materials.