The coasters serving as physical icons are depicted in Figure 9. The person holding the coaster, and only that person, has access to the information on the as- sociated exhibit. Each coaster is approximately inches in diameter, inches thick, and is made of a hollowed-outCorian base and a clear acrylic cap. An image of the associated exhibit is attached to the bottom of the cap, as shown in Figure 9. One component of the tagging system used to iden- tify the coasters and retrieve the associated data is a radio frequency identification device (RFID) tag em- bedded in the coaster. The tag, shown in the fore- ground of Figure 9,.
