for 循环中的未知函数‘corner’

Question

我想画这个图：正五边形的每一边都被五个圆点代替。

\documentclass[border=1mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{shapes.geometric}
\usetikzlibrary{calc}

\newcommand{\drawLineWithPoints}[2]{ 
  \foreach \i in {0,0.25,0.5,0.75,1} {
    \coordinate (point) at ($#1!\i!#2$);
    \draw (point) circle (2pt);
  }
}

\begin{document}
\begin{tikzpicture}
\node[minimum size=4cm, regular polygon, regular polygon sides=5] (a) {};


\foreach \i in {1,...,5}{
  \pgfmathtruncatemacro{\j}{\i+1}
  \ifnum\j>5
    \pgfmathtruncatemacro{\j}{1}
  \fi
  \drawLineWithPoints{(a.corner \i)}{(a.corner \j)}
}
\end{tikzpicture}
\end{document} 

但它向我显示了! Package PGF Math Error: Unknown function角落'（在'角落 0'）。'

如果我放弃 for 循环并\drawLineWithPoints逐一编写每个语句，它就可以正常工作。

\begin{tikzpicture}
\node[minimum size=4cm, regular polygon, regular polygon sides=5] (a) {};

\drawLineWithPoints{(a.corner 1)}{(a.corner 2)}
\drawLineWithPoints{(a.corner 2)}{(a.corner 3)}
\drawLineWithPoints{(a.corner 3)}{(a.corner 4)}
\drawLineWithPoints{(a.corner 4)}{(a.corner 5)}
\drawLineWithPoints{(a.corner 5)}{(a.corner 1)}
\end{tikzpicture}

为什么？