The 'simultaneous green' junction separates the movement of people cycling from motor traffic, by holding all motor vehicles at red signals, while people cycling have green signals to enter the junction, from any direction. Their paths may cross, but they negotiate with one another.
In this example in Assen, cyclists are progressing into the junction, while motor vehicles are held.
These kinds of junctions are a simple and effective way of removing the danger posed by conflicting turns with motor vehicles, although the amount of time given to cycling on the signals has to be set appropriately so that people are not delayed unnecessarily.