Many coalitions are possible. The problem is that many parties have excluded each other. The Flemish nationalist N-VA doesn't want to form a government with left wing parties, but at the same time is objecting to a federal government without a Flemish majority. Francophone parties reject co-operation with the far right Vlaams Belang and aren't at all happy about working with the N-VA. With present positions no coalitions seem possible.
In Flanders the far right and the nationalists could team up but require a third partner. None of the other parties are currently prepared to join in.
The Flemish socialists say they are unwilling to enter government torpedoing a nationalist, liberal, socialist administration, a coalition that is already running Flanders largest city, Antwerp. The outgoing coalition of nationalists, Christian democrats and liberals could be revamped, but this only includes losers.
Ivan De Vadder believes that vetoes against parties could disappear overnight. After the elections parties adopt positions in the light of the result, but within weeks openings may appear in talks allowing adversaries to strike a deal. This can go very fast.
Like four years ago talks on the formation of the various governments are all happening at one and the same time. A deal on a new Flemish government will have implications for the federal talks. Walloon, Brussels and Francophone community coalitions all need to be brokered. One opening could unblock the entire situation across the various government levels.