I created another pattern,and used the chemical symbols, gold and silver.
copy layer and chaged to gradation color of central circle.
change to overlay only central circle.
As a result, it becomes visible the boundary line.
I thought the overlaid the two forms, not gradation processing is much better results.
This gradation effect I think that good results.
When I joined a"Steampunk"class, I wanted to create like this design and use 3D technique.
this time ,for the first time to learn how to use the 3D, it was very fun!
Thank you Helen!