\documentclass[12pt,twoside]{report}
\usepackage[margin=2cm]{geometry}
\usepackage{amsmath,amsthm,amssymb}
\usepackage{thmtools}
\usepackage{tikz}
\usepackage[framemethod=TikZ]{mdframed}

\declaretheoremstyle
[   spaceabove=0pt, spacebelow=0pt, headfont=\normalfont\bfseries,
    notefont=\mdseries, notebraces={(}{)}, headpunct={\newline}, headindent={},
    postheadspace={ }, postheadspace=4pt, bodyfont=\normalfont, qed=$\blacktriangle$,
    mdframed={   outermargin = 1.3cm , %
    leftmargin = 0pt , rightmargin = 0pt , %

\documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{calc}
\begin{document}
\begin{tikzpicture}
\foreach \x  in {1}{
  \pgfmathparse{100*\x}
  \edef\y{\noexpand\filldraw[fill=blue!\pgfmathresult!white, draw=black] (0,0) rectangle (\x,\x)}
  \y;
}
\end{tikzpicture}
\end{document}

\documentclass[border=2mm]{standalone}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\foreach \x [evaluate=\x as \tint using 100*\x] in {1,0.95,...,0}
\filldraw[fill=blue!\tint!white, draw=black] (0,0) rectangle (\x,\x);
\end{tikzpicture}
\end{document}

\documentclass{article}
\usepackage{xparse}
\ExplSyntaxOn
\NewDocumentCommand{\convertto}{mm}
 {
  \egreg_convertto:nn {#1}{#2}
 }

\cs_new:Npn \egreg_convertto:nn #1 #2
 {
  \fp_eval:n { \dim_to_fp:n { #1 } / 1#2 } #2
 }
\ExplSyntaxOff
\begin{document}
\convertto{1in}{cm}
\end{document}

\cs_new:Npn \egreg_convertto:nn #1 #2
 {
  \fp_eval:n { round( \dim_to_fp:n { #2 } / 1#1, 5) }\,#1
 }
\cs_new:Nn \xframed__all_option_output:
 {
  \tl_set:Nn \l_tmpa_tl { \begin{longtable}{@{}lll@{}}\caption*{Options}\\\hline\endhead }
   \tl_put_right:Nn \l_tmpa_tl { \multicolumn{3}{@{}c@{}}{length} \\\hline }
   \tl_put_right:Nn \l_tmpa_tl { \prop_map_inline:Nn  \l__xframed_length_option_prop {##1 & ##2 & \egreg_convertto:nn{cm}{##2}\\} }
   \tl_put_right:Nn \l_tmpa_tl { \\[-\baselineskip]\hline\multicolumn{3}{@{}c@{}}{skips} \\\hline }

\documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{calc}
\begin{document}
\begin{tikzpicture}
\coordinate (r) at (5cm,0cm);
\coordinate (h) at (0cm,5cm);
\foreach \x [evaluate=\x as \xeval using 2^\x] in {1,2,...,7}
\pgfmathparse{\xeval-1}\foreach \y in {0,1,...,\pgfmathresult}
\pgfmathsetmacro{\tint}{\x*10}
\pgfmathsetmacro{\col}{ifthenelse(mod(x,2),"blue","green")}
     \filldraw[fill=\col!\tint!white,draw=black,very thin]  ($ {\y/\xeval}*(r)+(h)-{1/\xeval}*(h)-{\y/\xeval}*(h) $) rectangle

\documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{calc}
\begin{document}
\begin{tikzpicture}
\coordinate (r) at (5cm,0cm);
\coordinate (h) at (0cm,5cm);
\foreach \x [evaluate=\x as \xeval using 2^\x] in {1,2,...,7}
\pgfmathparse{\xeval-1}\foreach \y in {0,1,...,\pgfmathresult}
\pgfmathsetmacro{\tint}{\x*10}
\pgfmathparse{ifthenelse(mod(\x,2),"blue","green")}
\let\col=\pgfmathresult
     \filldraw[fill=\col!\tint!white,draw=black,very thin]  ($ {\y/\xeval}*(r)+(h)-{1/\xeval}*(h)-{\y/\xeval}*(h) $) rectangle

\begin{document}
In some days I will write a documentation
\end{document}

% arara: pdflatex: { shell: true }
% arara: pdflatex: { shell: true }
\documentclass{article}
\usepackage{minted}
\usepackage{listings}
\usepackage{caption}
\captionsetup[figure]{font=sf,labelfont=bf,skip=\smallskipamount}
\usepackage{xparse}
\NewDocumentEnvironment {example} { mm  }
{\VerbatimEnvironment
 \captionof{lstlisting}{#2}\ifx\relax#1\relax\else\label{#1}\fi%
\begin{minted}[linenos=true]{latex}}
{\end{minted}}
\NewDocumentEnvironment {xexample} { o o  }
{\VerbatimEnvironment
  \IfNoValueF { #1 }%

% arara: pdflatex: { shell: true }
% arara: pdflatex: { shell: true }
\documentclass{article}
\usepackage{minted}
\usepackage{listings}
\usepackage{caption}
\captionsetup[figure]{font=sf,labelfont=bf,skip=\smallskipamount}
\usepackage{xparse}

\NewDocumentEnvironment {example} { mm }
 {\VerbatimEnvironment
  \captionof{lstlisting}{#2}\ifx\relax#1\relax\else\label{#1}\fi%
  \minted[linenos=true]{latex}}
{\endminted}

\ExplSyntaxOn
\keys_define:nn {xexample}
 {
  caption .tl_set:N = \l_mdxex_caption_tl,