Protection for a design under this chapter shall be available
notwithstanding the employment in the design of subject matter excluded
from protection under section 1302 if the design is a substantial
revision, adaptation, or rearrangement of such subject matter. Such
protection shall be independent of any subsisting protection in subject
matter employed in the design, and shall not be construed as securing
any right to subject matter excluded from protection under this chapter
or as extending any subsisting protection under this chapter.