Erri81
Written on June 24, 2019
% Dans le préambule
% -----------------
\usepackage{chemfig}
% -----------------
\begin{tikzpicture}
\coordinate(O) at (0,0);
\coordinate(A) at (45:3);
\coordinate(B) at ({3*cos(45)},0);
\draw (O)--(A)--(B);
\draw[fill=white] (A) circle(0.2);
\draw (A) node{$\bullet$};
\draw[fill=lightgray](45:1) --++(135:0.4)
--++(-135:0.4) --++(-45:0.4) --cycle;
\draw[fill=gray](A) ++(0.1,-1) --++(0.2,0)
--++(0,-0.2) --++(-0.2,0) --cycle;
\draw[thick] (45:1)++(135:0.2)--++(45:2) arc (135:0:0.2) --++(0,-1);
\end{tikzpicture}