Carroll diagram Carroll diagram A Carroll diagram, Lewis Carroll's square, biliteral diagram or a "two-way table" is a diagram used for grouping things in a yes/no fashion. Numbers or objects are either categorised as 'x' (having an attribute x) or 'not x' (not having an attribute 'x'). They are named after Lewis Carroll, the pseudonym of Charles Lutwidge Dodgson. Although Carroll diagrams can be as simple as the first one above, the most well known types are those similar to the second one, where two attributes are shown. The <nowiki>'</nowiki>universe<nowiki>'</nowiki> of a Carroll diagram is contained within the boxes in the diagram,
Pen name may use different pen names for each, sometimes with no attempt to conceal a true identity. Romance writer Nora Roberts writes erotic thrillers under the pen name J. D. Robb (such books are titled "Nora Roberts writing as J. D. Robb"); Scots writer Iain Banks wrote mainstream or literary fiction under his own name and published science fiction under Iain M. Banks; Samuel Langhorne Clemens used the aliases Mark Twain and Sieur Louis de Conte for different works. Similarly, an author who writes both fiction and non-fiction (such as the mathematician and fantasy writer Charles Dodgson, who wrote as Lewis