Why do candy bars have a zig zaggy pattern on the bottom?

Look at the underside of many candy bars (Snickers, Twix, etc). They have this distinctive zig-zag pattern on the bottom. What is its purpose?

Conveyor belt marks? Just a WAG

http://www.quora.com/Why-do-chocolate-bars-have-a-wavy-pattern-on-the-bottom

That just leaves the “why” they use that kind of fabric belt.
I would guess that it’s important that the product doesn’t slide about, and that the gaps between adjacent products are maintained.

And I would guess speed compared to the smoother/finer belts used for “fine chocolates”.

Everyone else has already hit the nail on the head with this one. I would just like to add that I’ve used the absence of such a pattern as a method of verifying that chocolates were hand made. While visiting Brussels, we ended up needing to buy decent Belgian chocolates with very little time. We were in Grand Place, which is rather overpriced and touristy. I wanted to be reasonably certain that we were getting handmade chocolates, so I checked one of the clear plastic bags and noticed that the bottoms of each chocolate were smooth.

I’m sure some fancier chocolate factories might have smooth conveyor belts (Godiva, perhaps?), but AFAIK a handmade chocolate will also have a slightly concave bottom due to the meniscus formed by the chocolate against the mold.