A form of cross-country training originally from Sweden, but adapted to a city environment. Like traditional backcountry fartlek, stoplight fartlek involves changing the tempo of the run, except instead of instinctually changing pace, the speed is governed by traffic and lights.

Internet persona(s) who happens to follow you and you happen to follow them back and maintain communication with and have a mutual liking for eachother whether it be friendship wise, etc. (Mutuals if more than one mutual)