You can duplicate (clone) a block definition to iterate on designs more quickly.
Open the block manager (cube icon on the left), then click the Clone/Duplicate icon on the Block Listing.
A new definition is added to the list with (copy) appended to the name.
Edit the block metadata to change the name, description, and keywords.
Place and edit the block to change the geometry and properties.
Note: Duplicating a block instance on the map does not create a new definition. Instead, it always adds another instance of the same block definition.