~/archiben wrote: ... what about the "S figure" version
Thankfully that's easier ?! ...
1. Construct the cocentric axis as before (line between the two circle centres)
2. Copy-rotate this line around both ends/centres to generate the perpendiculars (the pink/magenta lines)
3. Establish the intersection of these lines along the main axis ('X' marks the spot)
4. Draw a line -carefully- from here ('X') to the edge of one of the circles - and click when you get the perpendicular cursor.
5. Extend to the other circle