Challenge: find ways to make a circle in CA

[martin.novy]

Please post a yet another way to compute a rough circle using 8-bit CA.
I welcome both bitmap and vector circles ...

• bitmap: ( the boundary, or filled)
  
• vector: polygons with integer vertices, e.g. using the circular gliders from http://busyboxes.org/?size=40&trail=250 ... kpklOTtLA0