But why is one further in front of the other and slightly set above the other one ?
My educated guess would be to load into a rotary launcher, or to stack them in a weapons bay, just as you would layer arrows, in a bow mounted quiver, cock feather up, cock feather down in order to keep the feathers from impinging on one another, while having the shafts closer to one another.
The other possibility is a design/signature feature, ( as with the old Beechcraft Staggerwing), or the horizontally opposed cylinders of a BMW Boxer Motor?? some type of dynamic stability, yes they are odd, but they are efficient.
of greater interest to me are those two vertical stabilizers on top of the wing of the Tu-160??