Collapsable multi-level side menu?

Currently I am working on a project that requires multi-level side menu. Since the menu as taking too much space of the screen (non-english), I decided to make it collapsible so you can choose between the whole menu view, or the "icons only" menu view.

But I have problem with the menu items that are on multiple level, and I am not sure how to represent the icons on the second level when the menu is collapsed.