Is there a LaTeX package that paints a frame around text or paragraph - in the shape of the text (and not rectangular like for boxes)?

Question

For some intentional form given poems it might be of certain use, if a frame could be drawn around the text and lines. This is not similar to a simple box with rectangular form, but suits the form of the shape of the lines written.

Thank you for some hints, if available.

MWE:

\documentclass{report}
\begin{document}
\centering
This is\
an example  \
how it can be\
and should\
appear.
\vspace*{\baselineskip}
Without \
the lines \
around it. Can you\
imagine the\
lines?
\end{document}

The lines around the text need to be imagined. Is there a way or package to draw the lines closely to the text borders. Not a rectangular box!

See the image-file a follows:

A first look into tikz package gave to following code possibility for a solution, but which seem not yet satisfying. Reason: The separation between the outer line and the inner text is not sufficient. I tried inner sep=5mm but without effect (not included at the code below).

\documentclass{report}
\usepackage{tikz}
\usetikzlibrary{tikzmark}
\begin{document}
\centering
\tikzmark{A} \qquad \tikzmark{N}\
\tikzmark{B} This is \tikzmark{M}\
\tikzmark{C} an example \tikzmark{L}    \
\tikzmark{D} how it can be \tikzmark{K}\
\tikzmark{E} and should \tikzmark{J}\
\tikzmark{F} appear. \tikzmark{I}\
\tikzmark{G} \qquad \tikzmark{H}
\tikz[remember picture] \draw[overlay,thick,rounded corners=6pt] (pic cs:A) -- (pic cs:B) -- (pic cs:C) -- (pic cs:D) -- (pic cs:E) -- (pic cs:F) -- (pic cs:G) -- (pic cs:H) -- (pic cs:I) -- (pic cs:J) -- (pic cs:K) -- (pic cs:L) -- (pic cs:M) -- (pic cs:N) -- cycle;
\vspace*{\baselineskip}
\tikzmark{a} \qquad \tikzmark{n}\
\tikzmark{b} Without \tikzmark{m}\
\tikzmark{c} the lines \tikzmark{l}\
\tikzmark{d} around it. Can you \tikzmark{k}\
\tikzmark{e} imagine the \tikzmark{j}\
\tikzmark{f} lines? \tikzmark{i}\
\tikzmark{g} \qquad \tikzmark{h}
\tikz[remember picture] \draw[overlay,thick,rounded corners=6pt] (pic cs:a) -- (pic cs:b) -- (pic cs:c) -- (pic cs:d) -- (pic cs:e) -- (pic cs:f) -- (pic cs:g) -- (pic cs:h) -- (pic cs:i) -- (pic cs:j) -- (pic cs:k) -- (pic cs:l) -- (pic cs:m) -- (pic cs:n) -- cycle;
\end{document}

Answer 1

\draw plot[smooth cycle, thick] coordinates { ... } may give better results, together with shifting the \tikzmarks a bit upward. With tension=... you might get some funny, maybe not quite forseeable effects.

\documentclass{report}
\usepackage{tikz}
\usetikzlibrary{tikzmark}
\newcommand\ml[3]{% marked line
  \raisebox{0.5ex}[0ex][0ex]{\tikzmark{#1}}\quad
  #2\quad
  \raisebox{0.5ex}[0ex][0ex]{\tikzmark{#3}}%
}
\begin{document}
\begin{center}
  \ml A{}N\
  \ml B{This is}M\
  \ml C{an example}L\
  \ml D{how it can be}K\
  \ml E{and should}J\
  \ml F{appear.}I\
  \ml G{}H
\end{center}
\tikz[remember picture,overlay] \draw plot[smooth cycle, thick]
coordinates {(pic cs:A) (pic cs:B) (pic cs:C) (pic cs:D) (pic cs:E)
  (pic cs:F) (pic cs:G) (pic cs:H) (pic cs:I) (pic cs:J) (pic cs:K)
  (pic cs:L) (pic cs:M) (pic cs:N)};
\begin{center}
  \ml a{}n\
  \ml b{Without}m\
  \ml c{the lines}l\
  \ml d{around it. Can you}k\
  \ml e{imagine the}j\
  \ml f{lines?}i\
  \ml g{}h
\end{center}
\tikz[remember picture,overlay] \draw plot[smooth cycle, thick]
coordinates {(pic cs:a) (pic cs:b) (pic cs:c) (pic cs:d) (pic cs:e)
  (pic cs:f) (pic cs:g) (pic cs:h) (pic cs:i) (pic cs:j) (pic cs:k)
  (pic cs:l) (pic cs:m) (pic cs:n)};
\begin{center}
  \ml 1{}{14}\
  \ml 2{Without}{13}\
  \ml 3{the lines}{12}\
  \ml 4{around it. Can you}{11}\
  \ml 5{imagine the}{10}\
  \ml 6{lines?}9\
  \ml 7{}8
\end{center}
\tikz[remember picture,overlay] \draw plot[smooth cycle, thick, tension=3]
coordinates {(pic cs:1) (pic cs:2) (pic cs:3) (pic cs:4) (pic cs:5)
  (pic cs:6) (pic cs:7) (pic cs:8) (pic cs:9) (pic cs:10) (pic cs:11)
  (pic cs:12) (pic cs:13) (pic cs:14)};
\end{document}