Translator II: Grower, by Chicago-based artist Sabrina Raaf, is a rover robot which navigates hugging a room's walls and responding to the carbon dioxide levels in the air by drawing varying heights of "grass" on the walls in green ink.

Grower senses the CO2 level in the air via a digital sensor. The more people in an exhibit space breathing in oxygen and exhaling CO2, the higher the grass line.

By the end of an exhibition, the bases of all the walls in the space will be covered with fine green lines which together resemble a cross-section drawing of a field of grass. This simulated grass is just like the grass found in nature: it needs CO2 to grow.

Watching the artistic output of a machine sensitive to its environment makes the people in the space more sensitive to their environment too. Besides, the piece demonstrates how much art institutions depend on visitors to make thriving spaces for new art evolve and flourish.

You can see it along with other creative machines at the Peeler Art Center , Greencastle, IN., till November 28.