anchor.diff:                        (pla)
                         (sta countdown)))
                    (scroll-panels ()
  -                   `(poke 0 phase)))
  +                   `(poke 0 phase))
  +                 (stop-panels ()
  +                   `(poke 159 phase)))
   
           ;; Show them the circle.
           (repeat 192 linearly)
  
positive.code:         (repeat 88 split-by-4)
          ;; Slow down..
          (repeat 256
            (jsr 'split-by-4)
            (jsr 'spin-apart))
          ;; Rest and repeat. Come a little unglued.
          (repeat 256 spin-apart)
          (repeat 253 spin-apart)
  
negative.code: ;;;; This is a graphics demo. It horizontally scrolls a portion of
  ;;;; some artwork by Mark Ryden, in various colors, with some sinebobs
  ;;;; (?) and a wavy raster effect on top.  The art is converted from a
  ;;;; GIF file to an 8 KB character ROM during assembly. The image is
  ;;;; large enough that we need some timed code to switch pattern table
  ;;;; banks mid-frame.  It also incorporates an NSF file to provide
  ;;;; some crude music.
  
  ;;;; I'm no demo coder. Expect no 6502 wizardry here.
  
  ;;;; It targets a basic NROM board (32KB program, 8KB character). I
  ;;;; haven't had a chance to test on real hardware yet.
  