Marc decides on his turn to block 2 Danger Cubes from being placed on the City Board. He can do so as the Event Card has an outlined rectangle and hence allows for blocking. The outlined space on the card is green, hence can be blocked with a green resource (Leadership brick). He pays for this action by drawing a Leadership resource brick from HQ Tower and places this brick on the outlined space on the Event Card. When this event card becomes due to be resolved, only the visible effects on the card will trigger and the rest is blocked by the brick. After resolving the Event the brick on the card comes back on top of the HQ Tower as any other spend brick. Marc could have also blocked other Event cards in the same turn, if there would have been other Event Cards with outlined spaces.