- lighting fixtures, their aesthetics and the symbolism associated with them
- works centred around chess pieces, playing cards, the periodic table, countries, sets of items with a range of unique qualities
- windows, the various types and how designers take liberties with form while maintaining function
- codes, riddles and other ways of encrypting a message such that it is not immediately apparent
- symbolism when well-done
- certain words: "alimony", "remora", "aluminium", "promenade", mostly alveolar and postalveolar consonants
- birds
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