%!PS
% Illustrates clever 3D effect
% Joseph O'Rourke
% From p.68 of Bluebook (but with my comments)

300 500 translate


% p.68 of Bluebook

/Times-Roman findfont  
72 scalefont           
setfont


/printZip {
    0 0 moveto (Zip) show
} def

% Remember: [1 = white; 0 = black] setgray

%start incr end
0.95 -0.05 0 {
    % Uses the loop variable on the stack as the grey value!
    % Starts nearly white (.95), ends black (0)
    setgray printZip 
    -1 0.5 translate  % left and up
} for

% Overwrite last black lettering with pure white.
1 setgray printZip


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