To create a new block, use the Add method.
This method requires two values as input: the location in the drawing where the block is added and the name of the block to create.
Once created, you can add any geometrical object, or another block, to the newly created block. You can then insert an instance of the block into the drawing. An inserted block is an object called a block reference.
You can also create a block by using the WBlock method to group objects in a separate drawing file. The drawing file can then be used as a block definition for other drawings. AutoCAD considers any drawing you insert into another drawing to be a block.