One of the most striking details of the Sauber C36 is its lack of a roll hoop, instead of having the conventional hoop as a roll over structure with the main combustion air intake in the centre of that hoop the Sauber features a ?blade’ with the air intakes for cooling and combustion either side of it. The central structure is the component which passes the crash tests and is meant to protect the driver in the event of a roll over accident.

On the Sauber design the twin ducts either side of the roll structure are themselves split into segments (rather like the 2016 Mercedes and the 2017 Williams). The central and largest segments, those closest to the roll blade, feed the combustion air to the Ferrari V6 engine, the yellow air filter is just visible in the image above. The outer segments are separated from the combustion duct by a thin composite vane, these outer segments are likely for ERS cooling.
Below the main duct and to the side of the head rest further cooling ducts can be seen, note also the forward sweep of the roll hoop.

While some newer observers of Formula 1 may not have seen such a design before you do not have to go back too far to find very similar concepts in use. The design is in essence the same concept used by Mercedes in 2010 on the MGP W01 (above) and the following year on the Lotus TL11/T128 (below) and also the Force India VJM04

It is said that this approach gives better flow to the rear wing, but can create issues with even airflow...