  fstar = GP.sampleprior(xstar);
    clf
    <span class="keyword">for</span> ii = 1:5
        camlight
        lighting <span class="string">gouraud</span>
        hh(ii) = patch(isosurface(xeva, yeva, zeva, reshape(fstar,size(xeva)), levels(ii)));
        set(hh(ii), <span class="string">'Facecolor'</span>, cmap(ii,:), <span class="string">'Edgecolor'</span>, <span class="string">'none'</span>, <span class="string">'facealpha'</span>, (1-(5-abs(levels(ii)))/5));
        axis([-3 3 -3 3 -3 3])
        caxi