So they lie along the same exact plane. So they're essentially stacked on top of one another. Now remember, when they are stacked on top of one another, there are instantaneous dipole moments that exist within our bases. And those instantaneous dipole moments will interact with one another via the London dispersion forces. So not only do we have hydrogen bonding between the complementary adjacent bases, but we have the Vanderbilt forces, these London dispersion forces, between our bases stacked on top of one another. So these are H bonds, but these Brown bonds are essentially our London forces, the London Dispersion forces.