You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: spm_dem_reach_plot.m
    path of file: ./repos/malini/Codes/deconvolution - model/spm8/toolbox/DEM
    
    the code of the file until where you have to start completion: function [f]= spm_dem_reach_plot(DEM)

    
function [f]= spm_dem_reach_plot(DEM)
% plots the trajectory of a two-joint arm
% FORMAT [f]= spm_dem_reach_plot(DEM)
%
% DEM - DEM structure from reaching simulations
%__________________________________________________________________________
% Copyright (C) 2008 Wellcome Trust Centre for Neuroimaging
 
% Karl Friston
% $Id: spm_dem_reach_plot.m 3901 2010-05-27 16:14:36Z karl $

% evaluate positions
%--------------------------------------------------------------------------
x    = DEM.pU.x{1};
v    = DEM.pU.v{2};
N    = size(x,2);

T    = [v(1,end