- QBM reading/writing.  QBM files should support all the same data as QBE files
  but should be human-readable and -editable.  QBM files will also support any
  new features (such as more transformations) later added to qbism.

- Decent user interface.  I'm thinking of converting the qbism math to Tcl
  extensions and writing the user interface as Tcl script.

- No-discontinuity mode.  XOP_PROJECTION, XOP_SHIFT, XOP_SHIFTBACK, and
  XOP_CONDITIONAL sometimes introduce discontinuities which don't always look
  pleasant, but with a little work they can be tamed.

- Oversampling.  Oversampling makes the discontinuities look less crappy.

- Custom transformations.  If we're going to use Tcl, why not take advantage of
  its inherent scriptability?

And now some ideas for the user interface...

- History.  It's important to be able to go back in event of a click leading to
  a less-desirable family of algorithms.

- Adjustable preview size.  64x64 may be good, but sometimes the user will want
  to look a little closer.

- Adjustable sine wave.  The frequency multiplier and phase offset represent a
  great way to make tiny tweaks to the resulting output.

- Adjustable coarseness.  The "coarseness," a term borrowed from AMIGA Qbist,
  is the amount of variation between algorithms in a family of alternatives.

- Interactively editable algorithm.  The algorithm may resemble an assembly
  language program.  This is essentially the same as the QBM output.