During the game Robinson Crusoe, you can "invent" items around camp, and some items act as prerequisites for others. E.g. You cannot build a furnace without brick, and you cannot build a fireplace without fire.
Various events can destroy those items. On page 16, of the Portal Edition rulebook it states that when flipping a item card over, that "If the Item had an additional effect, you should cancel it if possible.
Assuming that a player has already built the "furnace" invention, after building the necessary invention "brick", and that an event forces the player to destroy the invented brick invention (as a choice among those available), then does that mean the invented furnace is destroyed as well? Or does the furnace remain available, even after the brick is removed, because it was already invented?