Yinyang LISP Logo

The Yinyang Lisp Logo

                         The ancient and
         and beautiful Chinese yin-yang symbol
      represents  complementary but  harmonious
   relationship  between the combinatory calculus
   and  the    lambda  calculus    Each  is    universal
    computationally but one has no variables while
       the  second    must    treat   bound   variables
          correctly. Their  representative    symbols
             relate  by    180   degrees  rotation,
                                 λ  and Y

illustration and commentary by Guy L  Steel  Jr

Finally, discovered the origin of this lisp logo. It's by by Guy L Steel Jr, from the book The Little LISPer, by Daniel P. Friedman, Matthias Felleisen, as early as 3rd Edition in 1989.

• The Little LISPer, 3rd Edition
• by Daniel P. Friedman, Matthias Felleisen
• 1989
• https://www.amazon.com/Little-LISPer-Third-Daniel-Friedman/dp/0023397632

thanks to jollyjack5856 comment on YouTube Xah Talk Show 2025-03-30 Ep637 Wolfram logo, lisp logo, python logo, why python sucks

• The Little LISPer 3rd ed., 1989, has this EXACT picture on its title page.
• Maybe earlier editions had it, too.
• So its a long-known symbol.
• and the “Little” book was extremely popular at one point, among LISPers.
• So it has the λ (lambda) and the Y symbols there (for Y combinator), intertwined, inside a circle.
• that's the idea.

• the book says “cover by Guy L. Steele”. then it has the full page with the explanation with text in the form of a circle, stating “illustration and commentary by Guy L.Steele, Jr.” He is the famous LISPer, one of authors of the book “Common Lisp the Language”.