x  = -1:0.005:1;
sz = size(x);
a  = 0.05;
for i =1:sz(2)
    for j = 1:sz(2)
        bf(i,j) = ((x(i)^2-x(j)^2)*sin((x(i) + x(j))/a))/(x(i)^2 + x(j)^2);
    end
end
fig = figure('Position',[0 0 800 800]);
imagesc(bf);
colormap bone;axis off;
set(fig, 'color', [0 0 0]);