There's a kind of cookie here in Budapest called "Bell" cookies!

So I got some. They're kind of like Oreo cookies, but they're beige instead of dark brown. They have a simple "six-petal flower" design instead of the intricate Oreo design.

The "six-petal flower" design is like this: The cookies are circular in shape, and the surface is divided into seven regions. There is a little circular region in the middle (radius about 1/4 of the total cookie radius), and the remaining annulus is divided by radial lines into six equal pieces. The divisions between regions are like creases, like if you bake cookies and two of them grow together. You know what I mean -- it's the sort of place where the cookie breaks really easily, like a fault line.

Anyway, the two opposite sides of a cookie happen to have these fault lines lined up, so you can break the whole cookie in half really easily. The circular piece in the middle sticks with one side or the other, so actually one of the halves winds up bigger than the other. Due I suppose to the creamy filling, the little circle on the top always stays on the same side as the one on the bottom. (If it wouldn't do this, I'd finally be able to break one into two halves of equal size!)

They're really yummy and fun to play with. I've been eating a lot of them lately, as you might have guessed.

Actually I figured out it's not the creamy filling that makes them both stick to the same side. If I carefully open the cookie without breaking either side, I can eat the creamy filling, leaving the faces bare and separated. Then even so the middles almost always stick to the "same" side when I break the sides independently. To keep track of which side is which after separation, I have to nibble the cookie a little bit at one edge before I carefully separate it. Then later I can tell how they were aligned originally by re-aligning them according to the nibbled part.

I figure maybe the little circle is more strongly connected to one of the segments than to the rest, and due to how the cookie-making machine puts them together, both sides have their "connected segment" in the same place.

I haven't been able to verify this by identifying any visual signs of which segment is the "connected" one, though, and it seems that the cookies get jumbled before they're packed, since the cookie's orientation in the box doesn't seem to give any clue either as to which side the little circle will stick to. I just have to try breaking it to see which side it will stick to.

Also, being "more strongly connected" isn't all that strong a phenomenon, because if I take a broken cookie half that the middle is still attached to and break it again along another petal-crease, the middle always sticks to the bigger two-petal part rather than to the single petal getting broken off. So the "strong" connection must be between one and two "normal" connections in strength.

So I realized I can semi-test this theory by doing something I'd been wanting to try anyway: Carefully separating the two sides and then breaking them in half along "different" creases rather than along the "same" one (as judged by how the cookie stood prior to careful separation). I'd done this a few times before I figured out the "nibbling one side first" technique, but I didn't keep track of the results because I wasn't sure how to realign the cookie anyway.

So I tried this, and the results were very simple, although not what I expected. The result is that if you look at the two breaks as being almost the same, but just differing by a one-petal rotation, then the middle still almost always sticks to the same side for both halves. What I expected was that the middle would stick to the "same" side 2/3 of the time, and stick to "opposite" sides 1/3 of the time, depending on whether the "stongly connected petal" wound up on "opposite" halves or not.

I thought maybe this could be explained in terms of a "strong" connection plus a secondary "semi-strong" connection, or maybe in terms of a "stronger side", but I couldn't get it to work.

It has occurred to me that if there were a three-faced cookie, then you could break the three faces along the three different crease directions, and at least one pair of faces would have to have the middle sticking to "opposite" sides. But of course only two-sided cookies are in the box (and I don't know how you could have more sides anyway), so it's a moot issue.

I'm stumped. Any ideas?

(Let me know if any of this wasn't clear -- it would be clearer with pictures.)