It seems that I am in a design oriented mood today. I just ran across these Virtual Chopsticks. What's interesting here is the analysis of the processes that occurs while people learn how to use these tools.

Tools are expected to provide users with good metaphors in future interactive systems for intuitively manipulating “information” or virtual objects. Moreover, by using a "virtualized" tool, we can investigate varieties of new tools by simply changing the software parameters of the tool with a standardized interface. Through these experiments, we expect to obtain new knowledge to design a good/comfortable user interface. In addition, we also expect to analyze processes that occur while humans learn to use new tools. We adopt chopsticks for one of the trials of our technique because although they are very simple in form, they do have multiple functions.