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Comment by qwertox | Hacker News Reader

Did my adblocker accidentally filter out the explanation?

Following the link which is supposed to explain another thing, why it is more resistant to lateral forces, it contains an explanation:

> The parameter a is the amplitude of the sine wave. If a = 0, we have a flat wave, i.e. a straight wall, as so the length of this segment is 2π = 6.2832. If a = 1, the integral is 7.6404. So a section of wall is 22% longer, but uses 50% less material per unit length as a wall two bricks thick.

"as a wall two bricks thick". Hmmm. Even bigger savings as a wall three bricks thick.

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The point is that a straight wall one brick thick will fall down.

Though I didn't see any real explanation of why a straight wall one brick thick will fall down...

Ever built Lego?

Maybe, a long time ago.

For those whose childhood is a long way behind them, would you explain?

Lego are just like those brick. If you just pile them on you have no strength, if you interlock them you have strength in one direction, if you have 2 rows interlocked, you have strength in 2 directions.

Imagine a posterboard, one of those 3 section things you can by at a supermarket kids use in science fairs. What happens if you attempt to stand that posterboard up with the sections in a strait line? Now take the outer two sections and place them at an angle to the central board. One will fall over by itself. The other will stand upright and even take a non-trivial amount of downward pressure (weight) before it falls over.

It works the same way with any thin and tall building, it needs to have support perpendicular to the main body. You'll note that most straight brick walls have thicker "towers" at regular intervals. Or it needs underground support, like concrete in the ground for a fence post.

Unrelated: Go buy a lego set! If you've forgotten the joy of LEGOs I encourage you to rediscover it. The kinds of sets they have available these days are vast and the cleverness of their building techniques needs to be seen to be appreciated.

The base proportion to the height.

Two bricks wide has a 2x wider base.

It doesn't have the vertical stability to stand on its own. You need to make it thicker (how thick depends on how tall, but the important aspect is the staggered construction of multiple layers giving a similar self-reinforcement) to give it the proper foundation. Keep in mind that it's multiple thin horizontal layers held by a relatively weak adhesive, not a solid object.

A wavy wall reinforces itself against the same forces (wind being the big one) allowing for thinner construction at an equivalent height.

Take a piece of paper. Try to put it on its edge. Now bend the paper in zigzag and try again

You need to use two brick width for stability.

Is that what we're doing? If I remember correctly, the walls around the houses in my childhood neighborhood were only one brick in width. Also walls around cemeteries and such, I could swear they are not double-width walls.

One brick wide walls often have a thicker pillar for stability every couple of meters.

And two brick thick walls often have pillars... So pillars aren't a good indicator.

Those are just veneers. My grandfather was a professional brick and stone mason. You can tell if a brick wall is load bearing if it has alternating directions: every so many bricks you’ll see one or more that’s been rotated 90° to connect the layers together

Veneer, all the bricks are in the same orientation: https://i.pinimg.com/originals/1b/65/ec/1b65ec6fdb488d3dab28...

Supporting wall, notice the alternating pattern: https://www.backwoodshome.com/bhm/wp-content/uploads/2015/12...

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