%!
% From hobbit@pyrite.rutgers.edu Thu Dec  1 21:39:54 1988
% Date: Thu, 1 Dec 1988 3:49:17 EST
% From: *Hobbit* <hobbit@pyrite.rutgers.edu>
% Subject: Yow!! It's *snowing*!

%%% bisymmetric snowflake attempts, v2.1 and this time we're going to get it
%%% right and mail it out this year.
%%% Enters with a number for "srand", or defaults it to something dumb

% prelude with srand arg if you want it
count 0 ne {srand} if	% allow for lossage if empty stack

% Stub of pause if not in NeWS
systemdict /pause known not {
  /pause {} def
} if

%% Randomize "draw" routine for this one: Special one for the walls -- 
%% reverse video, rnd grayscale [within reason]
/whichdraw [
  {scribble} {fscribble} {rorsch}
  ] def
%% Setgray turns out to be sort of a luse, at least for the black sheets.
/draw {1 setgray whichdraw 0 3 Rnd get exec} def
/points 200 array def	% storage...

/Rnd {			% arg1 arg2 Rnd -> abs-val int between arg1 and arg2
  2 copy sub abs rand 2 31 exp div mul cvi	% between 0 and difference
  3 1 roll 2 copy ge {exch} if pop add
} def  % Rnd

% Stuff the generated point in the array and fix the index; syntax is
% X Y logpoint, or rescue -> X Y
/logpoint { 2 { points idx 3 2 roll put /idx idx 1 add def} repeat } def
% Retrieve a point, leaves it on the stack
/rescue { 2 { points idx get /idx idx 1 add def } repeat exch } def

% Point generation loop should describe one half of one arm.  It is mirrored
% and duplicated six times around.

/rorsch {		% funny back-to-back out-and-in thing
  /Cy 0 def 
  /finalroutine {fill} def		% big ugly splotches
  /width 50 120 Rnd def			% *randomize* the width [change here]
  0 0 logpoint				% start at origin
  { 5 width Rnd Cy logpoint		% stuff it in
    /Cy Cy 2 40 Rnd add def		% Cy increment; change limits here
    Cy 250 ge { exit} if } loop		% diameter limit: change here
} def  % rorsch

% different one, random lines until the cows come home
/scribble {
  4 setlinewidth
  15 25 Rnd { 0 100 Rnd 0 250 Rnd logpoint } repeat
  /Cy 0 250 Rnd def
} def				% /scribble  

% scribble but then inter-fill some of the spaces
/fscribble { scribble /finalroutine {eofill} def} def

/flake {
  /idx 1 def			% array pointer [from 1, not 0, wtf]
  /finalroutine {stroke} def	% defaults to stroke; can be fill or...
%%% Select and perform array-generation algorithm above or as a prelude..
  draw

% Print one, mirror it, rotate the mess around, etc, etc ... puke...
  /imax idx def			% final array size, do until here
  6 { /idx 1 def newpath
    pause pause
    rescue moveto			% move to first one
    imax 2 idiv 2 sub { 		% arraysize - 2 ...
      rescue lineto } repeat
   0 Cy lineto closepath
% mirror image routine.  We come here with the so-far current path, and 
% reconstruct it backwards on the other side of the vertical.
    {exch neg exch moveto}		% move
    {exch neg exch lineto}		% line
    {curveto}
    {closepath} pathforall
% so do it, select fill or stroke above or in the algorithm, and finish up
    finalroutine
    60 rotate } repeat
} def  % flake

%% Now start the real work
erasepage 0 setgray clippath fill	% black!!

%% Okay, now randomize all that other dreck
10 20 Rnd {					% number per page
  gsave 50 500 Rnd 50 700 Rnd translate		% position
  5 25 Rnd 100 div dup scale			% size [% of 500]
  1 60 Rnd rotate				% rotation
  flake grestore				% do it!
} repeat
showpage
%%  _H*