A pulley system comprising: a first pulley rotatable about a first pulley axis, a first cable portion wrapped around the first pulley, such that, when the first pulley is rotated in a first direction about the first pulley axis, the first cable portion is unwound from the first pulley, and a second cable portion wrapped around the first pulley, such that, when the first pulley is rotated in the first direction about the first pulley axis, the second cable portion is wound further onto the first pulley, wherein the first and second cable portions form a continuous cable passing radially through the first pulley.