A zoom lens is disclosed that is formed of only two lens groups. The 3D client is able to interpret 3D structure definitions and display 3D environments associated with various sets of websites. The visited cell site history information is indicative of one or more visited cell sites of the WWAN that served the mobile device over a moving time period of its operation. The second gain can be changed by changing the two interconnection nodes connected to the third output node pair via the switch circuit.