borda sem flecha

Question

Eu estava tentando desenhar uma borda sem flecha. Quando eu faço isso:

\begin{tikzpicture}

\draw[thick] (0, 0) node[circle, draw](A) {};
\draw[thick] (A) edge[loop below] (A);
 
\end{tikzpicture}

Recebo uma seta mesmo não tendo especificado ">=" no código tikz. Tentei "edge[-,loop Below]" e ainda recebo a seta. Eu também tentei "edge[style={},loop abaixo]". Finalmente removi a flecha tentando a distância:

\begin{tikzpicture}

\draw[thick] (0, 0) node[circle, draw](A) {};
\draw[thick] (A) edge[loop below, distance=1cm] (A);
 
\end{tikzpicture}

Por que a distância desliga a seta? Estou faltando alguma coisa aqui?

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

\begin{tikzpicture}
\draw[thick] (0, 0) node[circle, draw](A) {};
\draw[thick] (A) edge[loop below] (A);
\end{tikzpicture}

\begin{tikzpicture}
\draw[thick] (0, 0) node[circle, draw](A) {};
\draw[thick] (A) edge[loop below, distance=1cm] (A);
\end{tikzpicture}

\end{document}

Answer 1

Não é uma resposta, mas inferindo do manual (75.4 Loops), pode estar analisando a lógica (talvez também interagindo com a definição de edge[loop], mas isso é um palpite).

O valor inicial é ->e loop belowos demais não possuem valor definido. Observe que isso edge[distance=10pt,loop below]produz uma ponta de seta.

MWE

\documentclass{article}
\usepackage{tikz}

\begin{document}
\center
\begin{tabular}{cc}
\begin{tikzpicture}
\draw[thick] (0, 0) node[circle, draw,pin={(A) edge[in=255,out=285,min distance=5mm] (A)}](A) {1};
\draw[thick] (A) edge[in=255,out=285,min distance=5mm] (A);
\end{tikzpicture} &
\begin{tikzpicture}
\draw[thick] (0, 0) node[circle, draw,pin={edge[->...}](A) {1};
\draw[thick] (A) edge[->,in=255,out=285,min distance=5mm] (A);
\end{tikzpicture}\\
\begin{tikzpicture}
\draw[thick] (0, 0) node[circle, draw,pin={(A) to [loop below] ()}](A) {2};
\draw[thick] (A) to [loop below] ();
\end{tikzpicture} &
\begin{tikzpicture}
\draw[thick] (0, 0) node[circle, draw,pin={\textbackslash draw[thick,->]...}](A) {2};
\draw[thick,->] (A) to [loop below] ();
\end{tikzpicture}\\
\begin{tikzpicture}
\draw[thick] (0, 0) node[circle, draw,pin={(A) edge[loop below, distance=2mm] (A)}](A) {3};
\draw[thick] (A) edge[loop below, distance=2mm] (A);
\end{tikzpicture}&
\begin{tikzpicture}
\draw[thick] (0, 0) node[circle, draw,pin={edge[->,...}](A) {3};
\draw[thick] (A) edge[->,loop below, distance=2mm] (A);
\end{tikzpicture}\\
\end{tabular}

\begin{tikzpicture}%[every loop/.style={}]
\draw (0,0) edge [red,loop above] () to [loop right] ()
to [loop below] () to [loop left] ();
\end{tikzpicture}
\begin{tikzpicture}[every loop/.style={}]
\draw (0,0) edge [loop above] () to [loop right] ()
to [loop below] () to [loop left] ();
\end{tikzpicture}

\begin{tikzpicture}
\node [circle,draw] {a} edge [loop above] node {x} ();
\end{tikzpicture}
\begin{tikzpicture}[every loop/.style={}]
\node [circle,draw] {a} edge [loop above] node {x} ();
\end{tikzpicture}

\begin{tikzpicture}
\draw[thick] (0, 0) node[circle, draw](Z) {};
\draw[thick] (Z) edge[red,distance=10pt,loop below] (Z);
\end{tikzpicture}
\begin{tikzpicture}
\draw[thick] (0, 0) node[circle, draw](Z) {};
\draw[thick] (Z) edge[loop below,distance=10pt] (Z);
\end{tikzpicture}
\end{document}