So now there isn't simple way to create such circles… ? It reminds me Mona Lisa in Powder Toy. (somebody painted it, presume by hand)
I try to create a circle some ways. For instance, I create Black Hole and surround it Nitrogen Ice. I used NICE, because it disappear completly, unlike water ice. I heat up hole and it consume some NICE, after that I filled space between NICE and Hole by Hole again and heat it. Repeat this, I create large ellipse (of Black Hole). The resulted circle is not ideal.