Physicist creates WiFi signal strength simulator

Cole found in his simulation he could get pretty good coverage even with his router in one corner of the room, but could get "tendrils of Internet goodness" everywhere if he placed the router right in the center of the apartment. In a simulation where he gave the concrete some absorption potential, he found a map more like what he expected: excellent reception immediately around the router, and beams that shone into various rooms with periodic strong spots from the waves' interference. — Arstechnica