\magnification \magstep2
\nopagenumbers

%% \otimes=\mathchar"220A is a \mathbin

$$
((A_1 \otimes A_2) \otimes A_3) \otimes A_4
=
A_1 \otimes (A_2 \otimes (A_3 \otimes A_4))
$$

\bye

%%%%%%%%

%% html tag

%%%% <img src="images/A1A2A3A4.png"
%%%%      alt="((A&#8321; &#8855; A&#8322;) &#8855; A&#8323;) &#8855; A&#8324; =
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%%%% no spaces
%%%%      alt="((A&#8321;&#8855;A&#8322;)&#8855;A&#8323;)&#8855;A&#8324; = A&#8321;&#8855;(A&#8322;&#8855;(A&#8323;&#8855;A&#8324;))"
%%%%      width="760" height="36">

%%%%%%%%

%% png creation (normal size, transparent)

%%% pdftex A1A2A3A4.tex
%%% pdftocairo -png -singlefile -transp -r 180 A1A2A3A4.pdf tmp
%%% magick -define png:exclude-chunk=date,time tmp.png -trim +repage A1A2A3A4.png
%%% optipng A1A2A3A4.png %% no effect

%%%% magick adds white (fallback) background to the transparent image
%%%% and has the convenient option -trim.

%%%% Image size is 760x36.

%% program versions

%%% This is pdfTeX, Version 3.14159265-2.6-1.40.20 (TeX Live 2019/Debian) (preloaded format=pdftex 2024.3.16)

%%% pdftocairo version 0.86.1
%%% ImageMagick 7.1.1-43 Q16-HDRI x86_64 22550 https://imagemagick.org
%%% OptiPNG version 0.7.7

%%%%%%%%

%%%% First version (using tex, dvipng):
%%% 2024-06-21

%%%% Recompiled:
%%% 2025-08-09

%%%%%%%%
