clear; % timestep DeltaT=0.1; % diffusion coefficients DX=0.2; DY=0.02; % reaction constants k1=1; k2=1; k3=1; k4=1; % initial concentrations X0=1; Y0=1; % constant concentrations A=1; B=3; % sigma of the random initial distortion initRandomSigma=2; % width/height of the simulation grid width=100; % number of iterations before display iterationsPre=3000; % number of visible iterations after pre iterations=300; iterationsDT=6; % number of visible iterations before pre iterationsStart=300; % number of visible iterations before pre iterationsInit=300; % number of invisible iterations before iterationsStart iterationsStartPre=600; % number of visible iterations after pre iterationsPre1=6000; % number of visible iterations after pre iterations1=300;     % laplace operator laplace=0.25*[0 1 0; 1 -4 1; 0 1 0];   % initialize reaction variables X(1:width,1:width)=X0+(rand(width,width)-0.5)*2*initRandomSigma; Y(1:width,1:width)=Y0+(rand(width,width)-0.5)*2*initRandomSigma; X(X<0)=0; Y(Y<0)=0; X(X>4.5)=4.5; Y(Y>4.5)=4.5;   Xi=X; Yi=Y;   % colormap rbmap(1:100,1:3)=0; rbmap(:,1)=((length(rbmap)-1)-(0:(length(rbmap)-1)))/(length(rbmap)-1); rbmap(:,3)=(0:(length(rbmap)-1))/(length(rbmap)-1);     figure(1) s=get(gcf, 'Position'); s(3)=250; s(4)=200; set(gcf, 'Position', s); mf=1; for it=1:(iterationsInit+iterationsStartPre+iterationsStart+iterationsPre+iterations+iterationsPre1+iterations1)     lapX=conv2(X, laplace, 'same');     lapY=conv2(Y, laplace, 'same');     vX=k1*A+k2*X.^2.*Y-k3*B*X-k4*X+DX.*lapX;     vY=k3*B*X-k2*X.^2.*Y+DY.*lapY;       % leave border as distrotion centers     vX(1:width,[1 width])=0;     vX([1 width],1:width)=0;     vY(1:width,[1 width])=0;     vY([1 width],1:width)=0;       if ((it<=iterationsInit) ...