I have created this arrow box,
with this MWE:
\documentclass[a4paper,11pt,openright]{book} \usepackage{tikz} \usetikzlibrary{positioning, shapes.arrows} \begin{document} \begin{tikzpicture} \tikzset{box/.style={arrow box, draw=blue}}; \node[box, arrow box arrows={west:2cm}] at (0,0){\begin{minipage}{5em}This is a side note, like a post-it, which explains the text on the left side of the page.\end{minipage}}; \end{tikzpicture} \end{document}
but I need this:
Any help?
Thank you very much.