Draw a function!

[jebem]

It took me about 5 minutes to update my HP Connectivity Kit, Virtual Calculator and Prime physical machine.
(Windows 7 and USB2 port)

Then, in a matter of fractions of a second, my Prime physical machine recognized linear, trigonometric, exponential and logarithm functions from my rudimentary sketching.

Then I tried to design a square wave, but it gave me a nice informative "Function not recognized" message.
A circle is not recognized or it is redesigned as an exponential.
A triangle waveform is redesigned as sinusoidal.
A sawtooth waveform is not recognized or is redesigned as sinusoidal.

Still, this is an unique and impressive feature that seems to be useful to learn math in schools, or to be used just to impress your friends at work, especially when we are talking about a pocket calculator device.