I would guess that it is to make a better mortar joint. Mortar is forced into these holes and holds the bricks together better. Also the holes make the bricks lighter and air in the holes acts as insulation. I moved your question out of math to where I hope you will get a definitive answers.
Yes, but . . . There are two kinds of hollow bricks. One is for veneer only, the other is used for structural construction.
A concave lens has a curved surface that curves inward on both sides, causing light rays to diverge after passing through. In contrast, a plano-concave lens has one flat side and one curved concave side, which also causes light to diverge but with less optical power compared to a fully concave lens.
because one side is concave and the other is convex
A slightly concave mirror will produce a magnified image. Most shaving mirrors have one flat side and one concave side. Try looking in each side to find the one that magnifies.
The shape of a concave lens is such that the middle part is thinner than the edge. If one side of the lens is flat, then the other side will be shaped inward like a cave, kind of like this: [( You can also have a concave lens where both sides are shaped inward, like this: )( You can even have a concave lens where one side is shaped outward, and the other side is shaped inward, as long as the inward-shaped side is more dramatic than the outward-shaped side.
A convexo-concave lens is a lens that has one side convex (outward bulging) and the other side concave (inward curving). This type of lens can be used to correct myopia (nearsightedness) by diverging light rays entering the eye.
Some examples of concave shapes include a crescent moon, a cave entrance, and the letter "C". Concave shapes have at least one inward curve or indentation and are often described as having a hollow or sunken appearance.
They can if they are curved inward (concave). We frequently see this in make-up mirrors that have a flat, or "regular" side, and a concave side that magnifies the image one sees in it.
Many graphs that appear concave from one side will appear convex from the other. A smooth graph is generally described as concave if it is increasing AND if the rate of increase is also increasing. In terms of calculus this requires the first and second derivative to be positive. A concave polygon is one in which at least one of the vertices forms a reflex angle.
Yes, when an object is placed less than one focal point away from a concave mirror, it will appear larger and magnified. This is due to the virtual image formed by the concave mirror that appears on the same side as the object.
Weigh 3 on one side, and 3 on the other. You have three options: left side is heavier, right side is heavier, both are equal. If they are equal, the heaviest brick is one of the remaining two. If one of the sides is heavier, weigh one on each side. Once again, you have three options: left side is heavier, right side is heavier, or both weigh the same. In the latter case, the third brick is the heaviest brick.
It's just like eye glasses. One side is concave and the other side is convex. And when you look though it it makes things bigger.