So these bonds here are coming out of the board and they're essentially perpendicular to the plane of the board. So these atoms here are basically coming out of the board. And so what that means is, for instance, this hydroxyl group points upward and this hydrogen group points downward. So we see for our D glucose molecule, which is an example of an aldo HEXOS. HEXOS means we have 123456 carbon atoms, and aldo means we have the aldehyde group on that first carbon. So for D glucose, an example of an aldo HEXOS, the hydroxyl group on the fifth carbon, this blue hydroxyl group on the fifth carbon basically attacks the carbon number one of this carbonyl group that is part of that aldehyde.