The house at the left has 2 floors and each one [floor] has a lamp (LED). Both LEDs are connected to an Arduino and individually controlled with a Raspberry Pi. Right now the program is as follows: when I receive new email both floors light up until I mark every new mail as read.
Communication between RPi and the Arduino is achieved using https://github.com/thearn/Python-Arduino-Command-API.
The code is on github.