\input{preamble-standalone.ltx} \begin{document} % Ex. No. 178 (Section 21.2.2 : Example with \tkzname{mark =||}) \begin{tikzpicture}[scale=.75] \tkzDefPoints{0/0/O,5/0/A,3/4/B} \tkzMarkAngle[size = 4cm,mark = ||, arc=ll,mkcolor = red](A,O,B) \tkzDrawLines(O,A O,B) \tkzDrawPoints(O,A,B) \end{tikzpicture} \end{document}