The practice of marking a series of symbols on sidewalks and walls to indicate nearby wireless access.
Typically with the SSID written above the symbol and Bandwidth below.
Inspired by the practice of hobos during the Great Depression to use chalk marks to indicate which homes were friendly.
I warchalked the secret government agency down the street!
a practice in which hackers draw a symbol in chalk on a wall or pavement to indicate the presence of a wireless networking node.