what is the best way to draw these?

i tried Tikz-Feynman, but diagrams are too big

You could search in symbols-a4.pdf, I think all of them should be available on one package or another. For example \multimapdotboth from pxfonts, \bigominus and \bigovoid from mathabx ...

@samcarter these are too small or mess with other packages (some commands have the same name).

@samcarter's favourite environment

\documentclass{article}
\usepackage{amsmath}
\begin{document}

\[
-\dfrac{1}{2}\bigl[
\dfrac{1}{3!}
\begin{picture}(12,10)(0,2)
\put(6,5){\circle{12}}\put(0,5){\line(1,0){12}}
\end{picture}
+\dfrac{1}{4}
\begin{picture}(32,10)(0,2)
\put(6,5){\circle{12}}
\put(12,5){\line(1,0){8}}
\put(26,5){\circle{12}}
\end{picture}
\bigr]
+\dfrac{1}{8}
\begin{picture}(24,10)(0,2)
\put(6,5){\circle{12}}
\put(18,5){\circle{12}}
\end{picture}
-\dfrac{1}{2}
\begin{picture}(12.5,10)(0,2)
\put(3,5){\circle*{3}}
\put(3,5){\line(1,0){8}}

@DavidCarlisle Picture mode forever!

@DavidCarlisle awesome

@DavidCarlisle Oh, but is that accessible? :P

@mickep I can access it

@DavidCarlisle Good for you. :)

@mickep for the rest, blame @UlrikeFischer if it is not properly tagged in the pdf

@DavidCarlisle Ah, of course.

@mickep or use picture mode from context and blame you

what about these?

@DavidCarlisle I don't think context has picture mode...

@samcarter can fill in the details

@john Yes, what about them?

(Graphic in formulas, like Penrose...)

@mickep you could input the version we have for plain, or you know you really want to show off metapost

my bad

anyone knows how to do these?

@DavidCarlisle Haha, you should have seen the examples in the ConTeXt meeting yesterday...

@john really you are better asking on the question and answer part of the site, that's what it's there for. Practically speaking that strains what is possible in picture mode so you want tikz or metapost or pstricks or ...

Done with metapost overlays... Horrible to read according to me, but up to the standards of some old Penrose book.

veryspecialgames.com/products/…

The old code in tex.stackexchange.com/a/35409 no longer compiles: I get Missing \endgroup inserted. Could I kindly ask any of the gurus to repair the code?

@AlbertNash it's just an artifact of standalone, use a normal class like article

@DavidCarlisle I wished people would stop to use that all the time ;-)

@DavidCarlisle Thx!