A joint team from Saarland University in Germany and the MIT Media Lab has developed a printable multitouch sensor film that you can cut to any desired shape.
Proposing cutting as a novel paradigm for ad-hoc customization of printed electronic components is truly ground breaking. The electronic ink-wires are printed through using conductive ink on flexible, thin film. Researchers have developed 2 configurations - star and tree.
They were also able to combine both layouts in a space-saving way, so that the sensor supports all basic forms - be it a heart, a tree, a cat, or whatever your heart desires.
This very direct manipulation allows the user to make virtually any surface touch-interactive, with a huge range of possible applications (interaction with home appliances, interactive walls used for discussions and brainstorming and novel ultra-thin computer interfaces); oh, and I forgot the best part: it's incredibly cheap!

“The factory costs are so low that printing our A4-size [8.27 x 11.69 or 210 x 297 mm] film on our special printer in the lab costs us about one U.S. dollar,” says Max-Planck Institute for Informatics researcher Jürgen Steimle.
He estimates that the technology will become publicly available sometime in 2017.