The article “Immaterials: Light painting WiFi” by Einar Sneve Martinussen was published about a year ago and I confess I have only just stumbled across this. It is an excellent piece of art meets engineering where LEDs and long image exposure times are used to visually map out Wi-Fi signal strength.
I found the piece interesting in itself but also because it makes an interesting comparison between Wi-Fi and Li-Fi. With Wi-Fi, to get the best data rate you must seek out the best signal strength – which is invisible. With Li-Fi it is obvious where the best data rate can be achieved – just find a spot which is well lit.