I don't know about circles, but I'll pace quite a bit, and I'm prone to walk in ellipses and other shapes. I tend to do this when I'm lost in thought about some topic, often my obsessive interest of the moment. Oddly enough, I also tend to do this when I'm having a conversation on the phone.
I experience the two aforementioned behaviors very differently, so I'm not sure why they both tend to bring about this particular behavior, but for whatever reason, that's just how it goes for me.
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"And I find it kind of funny, I find it kind of sad./ The dreams in which I'm dying are the best I've ever had."