An arrangement permitting a user for example in a internet point or using a different profile in the same machine can connect to a web server to download and install local client software such as a java application or a browser plug-in the first time he accesses to this service from that browser in order to customize his environment. The light-turning features may have angle-discriminating properties so that some light-turning features capture light incident upon the light guide at certain angles of incidence, but not others. A tile is removed from the display by unlocking the clamp portions. Additionally the header of packets entering the network are processed prior to entry or as part of the entry to the network to produce a processed packet.