Plasma demo by Bini Michele <mibintin.it>, Aug 1998. Public domain.
Coding time: ~5 hours.

TODO:
 - timing (currently the demo only runs at full speed).
 - better support for non-palettized displays?
 - mmx optimizations? (the main task of the code is summing three tables,
and mmx instructions could help).

Note from porting author: I remember having seen this effect already ported
 inside an archive called SDL-demos.lha with several SDL effects taken from
 the demo section of www.libsdl.org but this one is provided with sources,
  readme and is linked against latest PowerSDL thus offering much more options
  like being iconified or promoted to a new screen.

 PERMSSN    UID  GID    PACKED    SIZE  RATIO     CRC       STAMP          NAME
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[generic]                28202   70736  39.9% -lh5- 3426 Jun 22 00:31 plasma-1.0/plasma
[generic]                  223     311  71.7% -lh5- ee05 Oct  8  1999 plasma-1.0/README
[generic]                  546     924  59.1% -lh5- a58c Jun 22 12:14 plasma-1.0/README.morphos
[generic]                 2182    6036  36.1% -lh5- ff39 Dec 21  1999 plasma-1.0/sources/acinclude.m4
[generic]                 3733    9576  39.0% -lh5- f6f0 Dec 21  1999 plasma-1.0/sources/aclocal.m4
[generic]                  518    1151  45.0% -lh5- ebb4 Jun 22 00:30 plasma-1.0/sources/config.cache
[generic]                  432    1078  40.1% -lh5- 58aa Jun 22 00:30 plasma-1.0/sources/config.log
[generic]                 2062    5349  38.5% -lh5- 13bb Jun 22 00:30 plasma-1.0/sources/config.status
[generic]                14399   50094  28.7% -lh5- a8b2 Dec 21  1999 plasma-1.0/sources/configure
[generic]                  280     418  67.0% -lh5- 8f9f Dec 21  1999 plasma-1.0/sources/configure.in
[generic]                 2233    5598  39.9% -lh5- a21f Dec  6  1999 plasma-1.0/sources/install-sh
[generic]                 2942    8951  32.9% -lh5- 2c01 Jun 22 00:30 plasma-1.0/sources/Makefile
[generic]                   24      24 100.0% -lh0- 812a Dec  6  1999 plasma-1.0/sources/Makefile.am
[generic]                 2872    8745  32.8% -lh5- 26a2 Dec 21  1999 plasma-1.0/sources/Makefile.in
[generic]                 2135    6283  34.0% -lh5- b90d Dec  6  1999 plasma-1.0/sources/missing
[generic]                  380     722  52.6% -lh5- c7b6 Dec  6  1999 plasma-1.0/sources/mkinstalldirs
[generic]                 1420    3540  40.1% -lh5- 6236 Dec 21  1999 plasma-1.0/sources/plasma.c
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total        17 files   64583  179536  36.0%            Jul 10 15:31