\begin{tikzpicture}
% légende
\node[fill,active]    (active)    [label=right:Active]    at (0,-1) {};
\node[fill,frontier]  (frontier)  [label=right:Frontier]  at (2,-1) {};
\node[fill,quiescent]   (quiescent) [label=right:Quiescent] at (4,-1) {};

% background
\fill[fill=quiescent] (0,0) rectangle ++(5,5);

% base collection
\filldraw[very thick,frontier,fill=active,line width=3pt,
  scale around={0.8:(2.5,2.5)}]
 (3.3,0.5) .. controls +(30:1cm) and +(-60:2cm) ..
 (4.5,3.5) .. controls +(120:2cm) and +(20:0.5cm) ..
 (1  ,4.6) .. controls +(-160:0.5cm) and +(up:2cm) ..
 (0.4,1.5) .. controls +(down:2cm) and +(-150:1cm) ..
 (3.3,0.5);
\filldraw[very thick,frontier,fill=quiescent,line width=3pt,
  scale around={0.3:(3,2)}]
 (3.3,0.5) .. controls +(30:1cm) and +(-60:2cm) ..
 (4.5,3.5) .. controls +(120:2cm) and +(20:0.5cm) ..
 (1  ,4.6) .. controls +(-160:0.5cm) and +(up:2cm) ..
 (0.4,1.5) .. controls +(down:2cm) and +(-150:1cm) ..
 (3.3,0.5);

\pause
\fill[fill=active]
 (3.3,0.5) .. controls +(30:1cm) and +(-60:2cm) ..
 (4.5,3.5) .. controls +(120:2cm) and +(20:0.5cm) ..
 (1  ,4.6) .. controls +(-160:0.5cm) and +(up:2cm) ..
 (0.4,1.5) .. controls +(down:2cm) and +(-150:1cm) ..
 (3.3,0.5);
\fill[fill=quiescent,
  scale around={0.4:(3,2)}]
 (3.3,0.5) .. controls +(30:1cm) and +(-60:2cm) ..
 (4.5,3.5) .. controls +(120:2cm) and +(20:0.5cm) ..
 (1  ,4.6) .. controls +(-160:0.5cm) and +(up:2cm) ..
 (0.4,1.5) .. controls +(down:2cm) and +(-150:1cm) ..
 (3.3,0.5);
\fill[fill=quiescent,
  scale around={0.1:(2,4)}, rotate around={170:(2,4)}]
 (3.3,0.5) .. controls +(30:1cm) and +(-60:2cm) ..
 (4.5,3.5) .. controls +(120:2cm) and +(20:0.5cm) ..
 (1  ,4.6) .. controls +(-160:0.5cm) and +(up:2cm) ..
 (0.4,1.5) .. controls +(down:2cm) and +(-150:1cm) ..
 (3.3,0.5);

\pause
\filldraw[very thick,frontier,fill=active,line width=3pt]
 (3.3,0.5) .. controls +(30:1cm) and +(-60:2cm) ..
 (4.5,3.5) .. controls +(120:2cm) and +(20:0.5cm) ..
 (1  ,4.6) .. controls +(-160:0.5cm) and +(up:2cm) ..
 (0.4,1.5) .. controls +(down:2cm) and +(-150:1cm) ..
 (3.3,0.5);
\filldraw[very thick,frontier,fill=quiescent,line width=3pt,
  scale around={0.4:(3,2)}]
 (3.3,0.5) .. controls +(30:1cm) and +(-60:2cm) ..
 (4.5,3.5) .. controls +(120:2cm) and +(20:0.5cm) ..
 (1  ,4.6) .. controls +(-160:0.5cm) and +(up:2cm) ..
 (0.4,1.5) .. controls +(down:2cm) and +(-150:1cm) ..
 (3.3,0.5);
\filldraw[very thick,frontier,fill=quiescent,line width=3pt,
  scale around={0.1:(2,4)}, rotate around={170:(2,4)}]
 (3.3,0.5) .. controls +(30:1cm) and +(-60:2cm) ..
 (4.5,3.5) .. controls +(120:2cm) and +(20:0.5cm) ..
 (1  ,4.6) .. controls +(-160:0.5cm) and +(up:2cm) ..
 (0.4,1.5) .. controls +(down:2cm) and +(-150:1cm) ..
 (3.3,0.5);
\end{tikzpicture}