It just came from using what's already there, and I'm thoroughly convinced that if it's not phones, that there's always going to be enough there that you can build similar solutions that can be very effective in new contexts.
Wir verwendeten nur, was bereits vorhanden war. Ich bin überzeugt,  wenn es keine Handys sind, gibt es immer andere Ressourcen um ähnliche Apparate zu bauen, die in einem anderen Rahmen genauso wirksam sind.