via this auction
"This vintage Polyfusion quad panner, model QP-1, is very rare- there were only a couple of hundred ever made. It is the Holy Grail for Polyfusion modular synth owners , but would also be of interest to anyone who owns a recording studio or quad P.A. system. It features a joystick with amazing real time control, which allows you to move the sound from any quadrant to any other quadrant instantly, reverse direction, etc. There is also an auto and manual mode, which lets you do this either way. It was made famous by Pink Floyd, who still use it in their live show- it is what they use to move the sound around so convincingly on their quad system."
"As one of the first sequencers, it features a stunning capacity of 16 notes, which can be recorded in real time or step mode. (You can, however, loop a 16 note sequence infinitely.) Visually it is very cool to watch, as the LED above each note lights up as the sequence runs."
YouTube via tradlessons — May 01, 2010 — "ConcertinaXL is a 30-button Jeffries-style C/G Anglo Concertina for the iPad.
This video is of the upcoming 1.1 update which adds the optional drone and tremolo features.
Anglo concertinas are commonly used for playing traditional Irish dance tunes, and is a much-favored instrument in County Clare, Ireland.
The Anglo concertina is diatonic, meaning the instrument plays a different note for each button depending on whether you are pushing or pulling on the bellows.
In the app, to play, place the iPad on your leg and simply tip the iPad to the left for a bellows push note, or to the right for a bellows pull note, and press a button.
The PUSH/PULL display on the top of the screen shows which direction the bellows is moving.
You may reverse the bellows while pushing a button simply by tipping in the opposite direction.
Multiple buttons (up to 5) may be pressed at the same time to play chords.
Note guide (touch the 'i' icon in the center) shows the note names in realtime for each button when pushed or pulled.
Adjust the tilt sensitivity and volume using the sliders at the top of the screen. All settings are saved when the app exits.
Touch the Uilleann drone puck image to enable/disable a D-drone. The drone volume may be independently adjusted.
Touch in the diamond area at the bottom of the screen to do tremolo effects.
The button layout and spacing for the iPad exactly matches a real standard 30-button Jeffries-style instrument.
Uses extremely high-quality audio samples recorded from a high-end Anglo C/G concertina.
Up to 5 buttons may be pressed at the same time to make chords."