The images I find online are loaves that are apparently commercially made. They appear to be more long like a jelly roll. But I know what you meant. Others in the images took the log and shaped it in a kind of bunt or angel food pan, but that isn't it either. Think about what I described--

Roll your dough very flat, put your filling on it, and roll it into a straight log. Then take one corner of it and start to coil the log into a spiral on a cookie sheet; it rises there again then is baked. You get the spiral within the spiral. I found one image (link), it's a big sloppy one, not the neatly arranged and several rings that my mom did. Here's another.

Here is one being made though this filling being poured and mom's was dryer, had to be sprinkled and spread (but the outcome could be like my mom's poteca, though apparently these folks cut it and put it in a loaf pan) link. Here's the whole site: http://www.devichnik.ru/9912/recepty_ny.htm Is this any clearer now? People have gotten lazy, or had a different tradition, and it doesn't turn up the old fashioned way very often. I've made it only once or twice, but enough that I can see that the same recipe has simply been modified to a different shape, probably for automation.

SRS