function h = plottenbar(x)
if length(x) ~= 10; error('Input argument need to be of size x'); end
% Plots the ten bar truss with cross areas given in abs(x).
% If a component of x is negative its color is red otherwise blue.
% The numbering of the bars corresponds to the figure:
%
%    1     6
% 1-----2-----3
%  \   /|\   /|
%  2\3/ |7\8/ |
%    X 5|  X  | 10
%   / \ | / \ |
%  /   \|/   \|
% 4-----5-----6
%    4     9
%
y = abs(x);
nodeCoordinates = [
    0 2 %node 1
    1 2 %node 2
    2 2
    0 1
    1 1
    2 1]; % node 6

startAndStopNode = [
    1 2 %bar 1
    1 5 %bar 2
    2 4
    4 5
    2 5
    2 3
    2 6
    5 3
    5 6
    3 6]; %bar 10

h = figure;
axis([0 2.5 0 2.5]);
axis('square');
set(gca, 'Visible','off');
maxSize = max(y);
for i = 1:length(y)
    if y(i) > 0.01*maxSize
      hl = line([nodeCoordinates(startAndStopNode(i,1),1) nodeCoordinates(startAndStopNode(i,2),1)], ...
            [nodeCoordinates(startAndStopNode(i,1),2) nodeCoordinates(startAndStopNode(i,2),2)]);
      set(hl,'LineWidth', 10*y(i)/maxSize);
      if x(i) < 0 
           set(hl,'Color', 'red');
      else
          set(hl,'Color', 'blue');
      end
    end
end
end