I looked at
7 circles surrounded by 12 circles
and wanted to take it further, drawing a "tight" ring of $18$ circles (identical in size to the others) around the $12$, such that (a) the $18$ circles form a ring such that neighboring circles are tangential to each other and (b) if any circle in the outer ring touches a circle in the inner ring, they touch tangentially.
Further, I would like to extend it to more rings of $24, 30, 36, \dots$ circles in each ring -- all nicely tangential.
Any help would be appreciated!
As seen at the figure, up to $12$ surrounding circles are the congruent circles tangential.
For $12+6n, n=1,2,\dots \;$ surrounding circles, it seems more difficult to find a pattern (if any) that would make the circles tangential not only within the ring, but also "any circle from $(n)^{th}-$ ring tangential to a circle from the previous ring".