The idea behind was to have decorators on top of an icon. The idea is taken from eclipse, where it has a "background" icon and then a decorator for each edge (top left, top right, bottom left, bottom right). To stack up icons, such as user in the background and a plus as bottom right decorator.
Luckily this is possible with FA5, see here: https://jsfiddle.net/8oqL3b5p/276/
Taken this and combine it with ember, I was able to create this API: