Specify any additional factors to add to the design. For example, you can add a 9^{th} factor to an 8-factor design as *J = ABCDEFGH*. Use the following rules to add factors:

- Enter the added factors in alphabetical order, skipping the letter I which is the Identity element.
- The total number of factors in the design cannot exceed 15.
- Use a unique generator for each factor.
- Each generator is an interaction of factors in the base design.
- You can use a minus interaction for a generator, for example, D = -AB.

To block the design, list the block generators. You can use factors from the base design and factors that you add. The number of blocks in the design is 2^{p}, where p is the number of generators. For example, you can add four blocks to a 6 factor design by listing *ABCF ABDE*. For more information on blocks, go to What is a block?