Others have already said it but to show you, I found this on error-ref.com Here's the link: http://www.error-ref.com/incused-machine-doubling/ Error-ref is one of the many great sites to learn about error coins.
Wow ! The very few times you can't pull it right out your hat, you send us right to the source. You sir are quite the asset to this forum. I can dig it !
