As Stephen solves the math equation for Sargent he sees a little dance unfolding on the paper: "Across the page the symbols moved in grave morrice." A morris is an English folk dance in which a story is enacted by the costumed dancers—hence the following reference to "mummery." Stephen imagines the interactive algebraic symbols on the paper—"letters, wearing quaint caps of squares and cubes"—as figures moving in a morris dance: "Give hands, traverse, bow to partner."
The conceit is tiny, but exquisitely intricate. "Morris" comes from Middle English Moreys, because the dance was inspired by the Moors. The Moors in Spain also brought algebra (an Arab invention) to Europe; "so: imps of fancy of the Moors" in two different fields (mathematics and dance), which Stephen combines into a single fanciful image. The "quaint caps" that raise the dancing letters to the second and third power are mummers' hats, but they are also Moorish headcoverings, like the "whorled . . . emir's turban" that Stephen sees a few minutes later when he looks at the shells on Deasy's table.
Contemplating this ingenious little passage, one may recall Joyce's reply when someone told him that Finnegans Wake is trivial. "Yes," he said. "It is also quadrivial." One may further note the interest in Arabic, Islamic, and Middle Eastern culture that extends into thoughts about Averroes and Moses Maimonides a moment later, and takes many other forms in the book. This interest of Joyce's can be seen as early as the story Araby in Dubliners. In Finnegans Wake it is a frequent presence.
In Scylla and Charybdis the elements of the conceit in Nestor accrete again as Mulligan announces that he has "conceived a play for the mummers." Stephen looks at "The pillared Moorish hall" of the National Library, and thinks: "Gone the nine men's morrice with caps of indices." "Nine men's morrice" picks up Titania's phrase in A Midsummer Night's Dream 2.1.98, and Gifford notes that it is also the name of a checkers-like game, but Stephen seems still to be thinking primarily of those Moors who invented algebra. Their little number-men have "caps of indices": other numbers written above them, raising them to the second or third or fourth power. (In mathematical terminology "index," plural indices, is a synonym for "exponent" or "power": the number that says how many times another number should be multiplied times itself.)
 Leopold Bloom appreciates the kind of witty concatenation of motifs seen in Stephen's morrice dance, though he is not himself capable of it. He thinks admiringly on how all the pieces fit together in a saying of Molly's: "She used to say Ben Dollard had a base barreltone voice. He has legs like barrels and you'd think he was singing into a barrel. Now, isn't that wit. They used to call him big Ben. Not half as witty as calling him base barreltone. Appetite like an albatross. Get outside of a baron of beef. Powerful man he was at stowing away number one Bass. Barrel of Bass. See? It all works out."