function MTB_Week11_button1
hndl = uicontrol('style','push','BackgroundColor','w','units',...
    'normalized','position',[0.3 0.3 0.4 0.4],'visible','on');
set(hndl,'callback',@(scr,evnt)pushFcn(hndl));
end

function pushFcn(hndl)
    set(hndl,'BackgroundColor',rand(3,1));
end
