For anyone who wants to type or paste into the Code textarea:

* https://webdocs.cs.ualberta.ca/~hayward/papers/BLUEBOOK.pdf The PostScript Language Tutorial and Cookbook (the "Blue Book") (principally) by Linda Gass and John Deubert, 1986 (ISBN 0-201-10179-3)

* https://www.adobe.com/jp/print/postscript/pdfs/PLRM.pdf The PostScript Language Reference (third ed.—a later edition of the "Red Book") (principally) by Ed Taft, Steve Chernicoff and Caroline Rose, 1999 (ISBN 0-201-27922-8)

* https://connor.zip/resources/pdfs/adobe-green-book.pdf PostScript Language Program Design (the "Green Book") by (principally) by Glenn Reid, 1988 (ISBN 0-201-14396-8). A zipfile with Green Book code files: https://web.archive.org/web/20110613223722/http://partners.a...

(At first my retro-ps tab got itself into a state in which it would not run any code entered into the Code textarea, instead timing out and returning an error; and since page reload is soft-disabled you'll have to either force a reload or open a new tab. Also, since the Abobe sample code uses indentation extensively—for example the Blue Book's official "hello world" program is

  newpath
    144 72 moveto
    144 432 lineto
  stroke
  showpage

—it would be nice if the Code textarea handled Tab keyboard inputs. )