When you start streaming data in the GUI, there is a small tab on the right hand side of the screen which when clicked will open an accelerometer visualizer window. You don't need to have any electrodes plugged into the board, you can just stream noise and open the window to see how the visualizer works.
Comments
Yes, the X, Y, Z values are from the accelerometer, in 'G' units. But not in position units.
http://docs.openbci.com/software/02-OpenBCI_Streaming_Data_Format
http://openbci.com/forum/index.php?p=/discussion/644/interpretation-of-openbci-data-files-edf-conversion