In a post a few weeks ago I mentioned the Pogo Sketch Stylus by Ten One Design. That same company has released a proof of concept video demonstrating how the Pogo Sketch can be used as a pressure sensitive device on the iPad. Essentially, the harder you push down on the stylus, the greater the area of contact of the tip. Algorithms written by Ten One then interpret changes in the area of contact as simulated variations in pressure. However, Apple does not currently allow the use of such private software codes on the device, so this application isn’t available to a wider audience. Ten One is offering the underlying algorithms for free to developers, so perhaps we’ll see Apple take advantage of this capability in a future release of the iOS. More on this here.