Example: Poppy flower

% Poppy flower
% Author: Elena Botoeva
\documentclass{article}
\usepackage[margin=0.3cm, paperwidth=9.5cm, paperheight=9.5cm]{geometry}
\usepackage{tikz}
\usetikzlibrary{fadings}

\definecolor{darkgreen}{rgb}{0.2,0.6,0.2}
\definecolor{poppyred}{rgb}{0.89,0.08,0.3}
\definecolor{poppyredd}{rgb}{0.78,0.0,0.09}
\definecolor{poppyreddd}{rgb}{0.63,0.0,0.0}

\def\petala{
  [rounded corners=3] (0,0) %
  .. controls (-0.25,-0.5) and (-1.25,0.3) .. (-1.6,0) %
  .. controls (-1.6,0.75) and (-1.25,0.65) .. (-1.1,1) %
  .. controls (-1.05,0.65) and (-0.05,0.7) .. (0,0)}

\def\petalb{
  [rounded corners=3] (0,0)%
  .. controls (-0.55,-0.2) and (-1.25,0.7) .. (-1.5,0.6)%
  .. controls (-1.4,1.1) and (-1.15,0.9) .. (-0.75,1.4)%
  .. controls (-0.5,1.5) and (-0.05,1.45) .. (0.05,1.3)%
  .. controls (-0.15,1.1) and (0.25,0.05) .. (0,0)}

\def\petalc{[rotate=-30] \petalb}

\def\petald{[rotate=-90] \petala}

\def\petiolea{         
  [rounded corners=2] (0.25,-7) %
  .. controls (0.7,-5.5) and (0.3,-3) .. (0.25,-2) %
  .. controls (0.2,-1.5) and (0.33,-0.4) .. (0,0) %
  .. controls (0.34,-0.4) and (0.21,-1.5) .. (0.27,-2) %
  .. controls (0.4,-3) and (0.82,-5.5) .. (0.42,-7)
}

\def\petioleb{         
  [rounded corners=2] (0.1,-7) %
  .. controls (0.3,-3) and (-0.85,-1.05) .. (-2.3,-1) %
  arc (270:230:0.2)%
  .. controls (-2.7,-1) and (-3.05,-1.05) .. (-3.35,-1.3) %
  .. controls (-3.35,-1.5) and (-3.45,-1.75) .. (-3.65,-1.75) %
  .. controls (-3.7,-1.25) and (-3.4,-1.35) .. (-3.4,-1.25) %
  .. controls (-3.05,-0.95) and (-2.7,-0.9) .. (-2.4,-0.85) %
  .. controls (-1.1,-0.75) and (0.4,-2.45) .. (0.2,-7)
}

\def\petiolec{         
  [rounded corners=2] (-0.3,-7) %
  .. controls (-0.9,-3.5) and (-1.5,-2.7) .. (-2,-2.5) %
  .. controls (-2.5,-2.3) and (-3.2,-2.35) .. (-3.47,-3.5) %
  .. controls (-3.68,-3.85) and (-3.75,-4.2) .. (-3.9,-4.15) %
  .. controls (-4.0,-3.9) and (-3.8,-3.8) .. (-3.7,-3.8) %
  .. controls (-3.65,-3.75) and (-3.6,-3.7) .. (-3.5,-3.47) %
  .. controls (-3.2,-2.3) and (-2.5,-2.25) .. (-2,-2.45) %
  .. controls (-1.48,-2.65) and (-0.86,-3.5) .. (-0.26,-7)
}

\tikzfading[name=fade inside,
inner color=transparent!100,
outer color=transparent!30]

\tikzfading[name=fade out,
inner color=transparent!0,
outer color=transparent!100]

%%%------beautiful flower------%%%
\def\flower{
  % draw each petal independently
  \foreach \a in {\petala,\petalb,\petalc,\petald} 
  {
    \filldraw[draw=none,color=poppyred,opacity=0.8] 
     [postaction={path fading=south,fading angle=30,fill=poppyreddd,opacity=.2}]
    \a;
  }

  % draw all petals together
  \draw[draw=none,rounded corners=3] 
  [postaction={path fading=north,fading angle=30,fill=poppyreddd,opacity=.7}]
  \petala \petalb \petalc [rotate=30] \petald;

  % emphasise overlapping areas between two petals
  \begin{scope}
    \foreach \a/\b in {\petala/\petalb,\petalb/\petalc,\petalc/\petald} 
    {
      \begin{scope}
        \clip \a;
        \draw [draw=none]
        [postaction={path fading=fade inside,fill=poppyredd,opacity=.7}]
        \b;
      \end{scope}
    }
  \end{scope}

  % emphasise overlapping areas between three petals
  \begin{scope}
    \foreach \a/\b/\c in {\petala/\petalb/\petalc,\petalb/\petalc/\petald} 
    {
      \begin{scope} 
        \clip \a;
        \clip \b;
        \draw [draw=none]
        [postaction={path fading=fade out,fill=poppyreddd,opacity=.4}]
        \c;	
      \end{scope}
    }
  \end{scope}
}

\def\petioles[#1]{
    \foreach \a in {\petiolea,\petioleb,\petiolec} 
    {
      \draw[fill,color=#1] \a;
    }
}

%%% -----------POPPIES---------------- %%%

% beautiful poppy
\def\poppy[#1,#2]{         
  \begin{scope}[shift={#1},scale=#2]
    % draw the flower
    \flower;	
    
    % draw petioles
    \petioles[darkgreen]
  \end{scope}
}

% poppy with uniform color
\def\poppyu[#1,#2]{         
  \begin{scope}[shift={#1},scale=#2]
    % draw the flower
    \foreach \a in {\petala,\petalb,\petalc,\petald} 
    {
      \filldraw[draw=none,color=poppyred,opacity=0.8] 
      \a;
    }

    % draw petioles
    \petioles[darkgreen]
  \end{scope}
}

% black and white poppy
\def\poppybw[#1,#2]{         
  \begin{scope}[shift={#1},scale=#2]
    % draw the flower
    \foreach \a in {\petala,\petalb,\petalc,\petald} 
    {
      \filldraw[draw=none,color=gray!80,opacity=1] 
      \a;
    }

    % draw petioles
    \petioles[gray!80]
  \end{scope}
}

\begin{document}
\thispagestyle{empty}
\begin{center}
  \tikz\poppy[{(0cm,0cm)},1];
  \tikz\poppyu[{(4cm,0cm)},1];
  \tikz\poppybw[{(7cm,0cm)},0.8];
\end{center}
\end{document}