Below is an ultrasound scan of a human beatboxer's tongue whilst he's beatboxing... Use the slider at the bottom to start, stop and position the movie, as well as to turn looping off and on. Click here for a full-screen view.

(You'll need the Macromedia Flash plugin to play this, if it doesn't seem to work make sure you have the latest version from Macromedia's website: http://www.macromedia.com/go/getflashplayer)