\begin{debat}[\`A la recherche du point perdu]
Se mettre par équipe de quatre.
\begin{itemize}
 \item Reproduire chacun des schémas ci-dessous en vraie grandeur.\\ 
\begin{tikzpicture}[general, scale=0.7]
 \axeX{-3}{3}{0,1}
 \draw (0,0) node[above]{$O$};
 \draw (1,0) node[above]{$I$};
 \draw[<->, color=A1] (0,-0.6)--(1,-0.6);
 \draw (0.5,-0.6) node[below, color=A1] {\UniteGras{\ucm{3}}};
\end{tikzpicture}
\begin{tikzpicture}[general, scale=2]
 \draw (0,0)--(1,0)--(1,1)--(0,1)--cycle;
 \foreach \x/\y in {0/0, 0.9/0, 0.9/0.9, 0/0.9} {\draw (\x,\y) rectangle(\x+0.1,\y+0.1);} 
\foreach \x/\y/\N/\pos in {0/0/A/below left, 1/0/B/below right, 1/1/C/above right, 0/1/D/above left} {\draw (\x,\y) node[\pos]{$\N$};}
\draw (0.5,0) node[color=C1]{{\boldmath $\star$}};
\draw (0,0.5) node[color=C1]{{\boldmath $\star$}};
 \draw[<->, color=A1] (0,-0.1)--(1,-0.1);
 \draw (0.5,-0.1) node[below, color=A1] {\UniteGras{\ucm{3}}};
\end{tikzpicture}
\begin{tikzpicture}[general]
 \draw (0,0)--(3,0)--(3,2)--(0,2)--cycle;
 \foreach \x/\y in {0/0, 2.8/0, 2.8/1.8, 0/1.8} {\draw (\x,\y) rectangle(\x+0.2,\y+0.2);} 
\foreach \x/\y/\N/\pos in {0/0/A/below left, 3/0/B/below right, 3/2/C/above right, 0/2/D/above left} {\draw (\x,\y) node[\pos]{$\N$};}
 \draw[<->, color=A1] (0,-0.1)--(3,-0.1);
 \draw (1.5,-0.1) node[below, color=A1] {\UniteGras{\ucm{6}}};
 \draw[<->, color=A1] (-0.1,0)--(-0.1,2);
 \draw (-0.1,1) node[left, color=A1] {\UniteGras{\ucm{4}}};
\end{tikzpicture}
\begin{tikzpicture}[general, scale=2]
 \draw (0,0)--(1,0)--(0.5,0.87)--cycle;
\foreach \x/\y/\N/\pos in {0/0/A/below left, 1/0/B/below right, 0.5/0.87/C/above} {\draw (\x,\y) node[\pos]{$\N$};}
\draw (0.5,0) node[color=C1]{{\boldmath $\star$}};
\draw (0.25,0.435) node[color=C1]{{\boldmath $\star$}};
\draw (0.75,0.435) node[color=C1]{{\boldmath $\star$}};
 \draw[<->, color=A1] (0,-0.1)--(1,-0.1);
 \draw (0.5,-0.1) node[below, color=A1] {\UniteGras{\ucm{3}}};
\end{tikzpicture}
\item  Le professeur viendra placer un point
$M$ aléatoirement sur l'un des schémas.
\item Décrire avec précision la position du point $M$
afin que les autres groupes de la classe puissent 
essayer de le placer exactement au même endroit.
\end{itemize}
L'équipe qui arrivera à faire placer son point $M$ correctement par toutes les
autres équipes gagnera deux points, celle qui y arrivera  avec le moins d'informations gagnera trois points.
\end{debat}

