| 
 | 
 | 
Let a Circle 
 lie inside another Circle 
.  From any point on 
, draw a tangent to 
and extend it to 
.  From the point, draw another tangent, etc.  For 
 tangents, the result is called an 
-sided Poncelet Transform.
References
Dörrie, H.  100 Great Problems of Elementary Mathematics: Their History and Solutions.  New York: Dover,
  p. 192, 1965.