General Note:
	require an Apple IIe with 128k.  I don't use any advanced IIe 
	effects (no 65c02, no double-graphics modes).  I mostly just
	need the 128k of RAM for use as a RAM disk as it's next
	to impossible to load data while music is playing.

	Aside about the Disk II, Woz had an amazing design but it's
	controlled with cycle-accurae assembly bitbanging the hardware
	and is essentially hard real-time.  Interrupts or running other
	code while loading likely would make the disk fail.  I'm only
	aware of two demos that do this, X by French Touch and
	X by Y.  Haven't had a chance to look at what they did.

	Music is using my PT3 player that can play .pt3 tracker files.

	Disk code is by Qkumba.  It's super fast.  I'm using that with
	raw disk sector reads, there's no filesystem on the disk (no AppleDOS
	or ProDOS).


Intro
	horizontal scroll, a bit of a pain


Chessboard
	various ways to do this.
	cheating and using a sprite as didn't have time to hack up
	a 3d-render or else some sort of triangle-drawing code
	re-using existing sprite code, you can see artifacts on edges
	because the code is working at byte-granularity for speed
	but each byte holds 3.5 pixels.  One way to fix this is to
	have a separate mask sprite and oring things but that would
	severely reduce the frame rate and take up a lot more space

Tunnel
	I wasted a week trying to get a good tunnel effect and gave
	up (after some very interesting chunks of buggy code).
	Drawing circles is a pain on 6502.  So for this I just
	took 2 screenshots and page flip
	The real effect here is a bit more interesting that a plain
	tunnel as it wiggles the camera around too.


Interference
	This one is I think just interference between two circles.
	This one I used some existing code I had that was doing something
	vaguely similar with sine waves.  I didn't have time to try
	to do the proper effect.  Even with table lookups and self-modifying
	code and using lo-res the frame rate isn't high and it would probably
	be worse if I was doing the proper effect.  This effect does
	go on forever though.