The following designs are not registrable: Computer programs (section 1(3), RDA). Features of a product which are dictated by their technical function or which are necessary in order for the product or a product which is placed next to it to perform its function known as “must fit” exemptions (section 1C(1) and (2), RDA). However, a modular system of mutually interchangeable products, such as modular furniture or LEGO bricks, can be registered. “Must-match” products can also be registered. Designs contrary to public policy or accepted principles of morality (section 1D, RDA). Royal arms, or, without consent, a representation of the Royal Family (paragraph 1(1), Schedule A1, RDA). UK national flags, if the use would be misleading or grossly offensive (paragraph 1(2), Schedule A1, RDA). Coats of arms, national flags, official signs or hallmarks, or controlled symbols such as the Olympic Symbol, without consent (paragraphs (3) and (4), Schedule A1, RDA).