A method of associating an object with a sticker placed on a surface is disclosed. The sticker has coded data encoding a sticker identity. The sticker also has a region which exposes a position on the surface. The surface has coded data encoding surface identity and locations on the surface. The method starts by receiving indicating data from a sensing device which sensed the sticker and surface coded data respectively. The indicating data is indicative of the sticker identity, the surface identity and the position on the surface exposed by the sticker. The object is also identified, and the object is associated with the sticker identity, the surface identity, and the position on the surface exposed by the sticker.