This is an amazing robot created by David Bowen. Here is how he explains his Growth Rendering Device:

This system provides light and food in the form of hydroponic solution for the plant. The plant reacts to the device by growing. The device in-turn reacts to the plant by producing a rasterized inkjet drawing of the plant every twenty-four hours. After a new drawing is produced the system scrolls the roll of paper approximately four inches so a new drawing can be produced during the next cycle. This system is allowed two run indefinitely and the final outcome is not predetermined.

Read more about the Growth rendering device – via ComputerLove