Getting a good night's sleep can be a difficult task at the best of times, so how would you feel about trying to get forty winks while a robot immortalises you on canvas? It's all in the name of art, apparently: Ibis hotels in London, Berlin and Paris are seeking 40 volunteers for the project, which will involve a robotic arm sketching guests while they try to get some bed rest. The volunteers will sleep on special mattresses covered in sensitive grids that measure heat, pressure and sound. The data is then sent back to the robotic arm, which paints a picture in acrylics based on the subject's sleep patterns. Peaceful sleepers will wake up to find simple, straight lines on the canvas, while those who thrash around will have much more energetic "portraits". If you find the idea of a robot watching you sleep a bit creepy, don't worry: the arm is actually in a separate room, connected by a data cable. The sessions will take place on October 8th in Paris, October 26th in Berlin and November 4th in London - and if nothing else, volunteers get a free night's sleep in a hotel!