function show(elements, coordinates)
clf;
hold on;
axis on;
grid on;
for i=1:size(elements,1)
 edge(1,:) = [coordinates(elements(i,1),1), coordinates(elements(i,1),2),coordinates(elements(i,1),3)]; 
 edge(2,:) = [coordinates(elements(i,2),1), coordinates(elements(i,2),2),coordinates(elements(i,2),3)];
 plot3(edge(:,1), edge(:,2),edge(:,3),'-ro','LineWidth',2.0);
end 
view(20, 30);
title('geometry of the example')
