dynamic grid of toolbar icons in a dockwidget

Is it possible to have a QDockWidget with a grid of QToolButtons that will adjust when a user changes the size of the dockwidget?
Let's say we have 16 icons, and the dockwidget is wide enough for 4 columns, giving a 4x4 grid.
If the user makes the dockwidget only wide enough for 3 columns, then I want the grid to become 3x6 (a single icon in the 6th row).

You should have a look at the Flow Layout Example in Assistant.