手書き

\documentclass[b5j,10pt,twoside]{tetsujsarticle}
\usepackage{tetsuryoku}

\begin{document}
\pgfdeclaredecoration{penciline}{initial}{
    \state{initial}[width=+\pgfdecoratedinputsegmentremainingdistance,auto corner on length=1mm,]{
        \pgfpathcurveto%
        {% From
            \pgfqpoint{\pgfdecoratedinputsegmentremainingdistance}
                            {\pgfdecorationsegmentamplitude}
        }
        {%  Control 1
        \pgfmathrand
        \pgfpointadd{\pgfqpoint{\pgfdecoratedinputsegmentremainingdistance}{0pt}}
                        {\pgfqpoint{-\pgfdecorationsegmentaspect\pgfdecoratedinputsegmentremainingdistance}%
                                        {\pgfmathresult\pgfdecorationsegmentamplitude}
                        }
        }
        {%TO 
        \pgfpointadd{\pgfpointdecoratedinputsegmentlast}{\pgfpoint{1pt}{1pt}}
        }
    }
    \state{final}{}
}

\begin{tikzpicture}[decoration=penciline]
\draw[decorate,style=help lines] (-2,-2) grid[step=1cm] (4,4);
\draw[decorate,thick] (0,0) -- (0,3) -- (3,3);
\draw[decorate,ultra thick,blue] (3,3)  arc (0:-90:2cm); %% This is supposed to be an arc!!
\draw[decorate,thick,pattern=north east lines] (-0.4cm,-0.8cm) rectangle (1.2,-2);
\node[decorate,draw,inner sep=0.5cm,fill=yellow,circle] (a) at (2,0) {}; %% That's not even an ellipse !!
\node[decorate,draw,inner sep=0.3cm,fill=red] (b) at (2,-2) {};
\draw[decorate] (b) to[in=-45,out=45] (a); %% This was supposed to be an edge!!
\node[decorate,draw,minimum height=2cm,minimum width=1cm] (c) at (-1.5,0) {};
\draw[decorate,->,dashed] (-0.5cm,-0.5cm) -- (-0.5cm,3.5cm)  -| (c.north);
\end{tikzpicture}



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\pgfdeclaredecoration{free hand}{start}
{
  \state{start}[width = +0pt,
                next state=step,
                persistent precomputation = \pgfdecoratepathhascornerstrue]{}
  \state{step}[auto end on length    = 3pt,
               auto corner on length = 3pt,               
               width=+2pt]
  {
    \pgfpathlineto{
      \pgfpointadd
      {\pgfpoint{2pt}{0pt}}
      {\pgfpoint{rand*0.3pt}{rand*0.3pt}}
    }
  }
  \state{final}
  {}
}
 \tikzset{free hand/.style={
    decorate,
    decoration={free hand}
    }
 } 
\def\freedraw#1;{\draw[free hand] #1;} 

\begin{tikzpicture}
\freedraw [->](-5,0) -- (5,0); 
\freedraw [->](0,-5) -- (0,5); 

\freedraw[fill=blue!15,fill opacity=.25]  (-3,-3) rectangle (3,3);
\freedraw[fill=green!15,fill opacity=.25] circle [radius=3cm]; 
\freedraw[free hand,red,shift={(1,1)},rotate=45,fill=red!25,fill opacity=.5] %
          (1,1) -- (1,-1) -- (-1,-1) -- (-1,1) -- (1,1);
\freedraw[color=blue]   plot (\x,{sin(\x r)}) node [free hand,draw] {$\sin(x)$} ;     
\end{tikzpicture}

\end{document}