Working on the premise that usual shape for stamps is either square or rectangle,
I am sharing these two round stamps for the unusually -shaped stamps theme for Sunday Stamps.
The first stamp is from Portugal for the 2010 Campenato do Mundo de Futebol.
It was released on 31 May 2010.
The second stamp is an aromatic stamp from Russia
It's part of the series called the Gifts of Nature issued on 27 August 2003.
Other fruits on the series are pear, melon, wild strawberry, and apple.
On this second set, the first stamp is a cross with rounded edges from Finland.
It's from the theme Flora (Trees), with a birch bud printed on it.
It was issued 24 January 2011.
The hexagon stamp is from a set of 6, souvenir stamp called Bees of Taiwan.
Shown here is the Apis cerana or the eastern honey bee.
It was issued 12 July 2012.