L'art pour l'art: A design detail, expression or a sentence that has several vague meanings at once, but none of it make sense in context. The design detail or expression looks or sounds deep but it's not understood and can't be explained by the author. The author just hoped that more intelligent people would see it as intentional and make sense out of its involuntary originality, but without noticing that the author was just negligent. It can also be used sarcastically for design or writing that is not just bad.
Lace: Any form of unnecessary ornamentation. Iron rule. Strictly, categorically forbidden. Can be a sign of l'art pour l'art. See also: Icons.
Liverpool: Beginner's mistake in Information Architecture. Describes a set of titles arranged in a grid that each link to an overview page. Each title comes with a set of links below it, linking to subpages, typically separated by a vertical bar. The pattern was perfected on www.liverpool.gov.uk and is prominent on many websites from the Old Internet.