Here are two simple circuits I created to test the thermochromic ink. The patterns are not very obvious. I might need to press hard to make sure there is a contact between the circuit and the thermochromic ink.

As for the mini project, I drew some green leaves(white acrylic paint, blue and yellow ) on the oil painting canvas. So we I connect the Arduino to my laptop, the ink get heat and the leaves turn green into white. The idea of the project is to show the influence of global warming, environmental issues might cause species extinction, so we need to save energy to protect our environment.