On X/Twitter, I saw a drawing by 黄餅もち.

It is pretty easy to do in TikZ, so I quickly made this drawing, using LuaLaTeX:

The code is:

\documentclass[tikz,border=10pt]{standalone} 
\usepackage{luatexja-fontspec}
\usetikzlibrary{trees}
\begin{document}
\begin{tikzpicture}[edge from parent fork right,
  grow=east, every node/.style={draw}]
\node {あ}
  child { node {う} }
  child { node {い}
    child { node {お} }
    child { node {え} } };
\end{tikzpicture}
\end{document}

Click on “Run LaTeX here” to get it as a PDF.

Learning TikZ is challenging but really rewarding. A good book can help learning the basics quickly, such as TikZによるLaTeXグラフィックス.

See also: Original Source by Stefan Kottwitz

Note: The copyright belongs to the blog author and the blog. For the license, please see the linked original source blog.