This app is a personal seismograph. It visualizes the accelerometer data that your phone is receiving and illustrates the X, Y and Z readings in a seismograph style display. This turns out to be a handy tool for checking the amount of vibration that the phone is receiving from anything that you can attach your phone to, including yourself and the Earth! It is also handy for many other things, for example, balancing helicopters and quadrocopters.