Lex has a set of four cubes, each with a letter on each of its six faces. Each of the 24 faces is different.

Lex was playing with these cubes the other day and formed the following 16 words:

    OPEN   OWNS   TERN   FEUD
    GAUD   PAUL   DAZE   AVOW
    IAMB   XYST   BUND   CUKE
    DEFY   RICE   HOPS   SHUT

Identify the letters found on each cube; the order of the cubes doesn't matter.

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Adapted from BENT Brain Ticklers, Winter 2024.