Yes it can- that's the first thing I tried- but it will not iterate forever. The trick is to use indirect recursion: <div id="a"></div> <div id="b"></div>

Yes it can- that's the first thing I tried- but it will not iterate forever. The trick is to use indirect recursion: <div id="a"></div> <div id="b"></div> #a, #b { height: 200px; width: 200px; border: dashed; } #a { background: -moz-element(#b) no-repeat; background-size: 80%; border-color: green; } #b { background: -moz-element(#a) no-repeat; background-size: 80%; border-color: purple; }