1 The word ‘row’ as used here is a double-entendre, referring both to a line of cards in the matrix, and a row—the British term for an argument or altercation.
2 S. W. Erdnase is a pseudonym used by the author of The Expert at the Card Table, a book detailing sleight of hand, cheating and legerdemain using playing cards. Still considered essential reading for any card magician, the book, known also as either the Bible or, commonly, just Erdnase, has been in continual publication since 1902. Erdnase’s true identity is one of the enduring mysteries of the magic community.
3 In geometry, a point reflection or inversion in a point (or inversion through a point, or central inversion) is a type of isometry of Euclidean space. An object that is invariant under a point reflection is said to possess point symmetry; if it is invariant under point reflection through its center, it is said to possess central symmetry or to be centrally symmetric.”
4 In number theory, a semiperfect number or pseudoperfect number is a natural number n that is equal to the sum of all or some of its proper divisors. A semiperfect number that is equal to the sum of all its proper divisors is a perfect number.
5 A triangular number or triangle number counts the objects that can form an equilateral triangle. A square triangular number (or triangular square number) is a number which is both a triangular number and a perfect square. There are an infinite number of square triangular numbers; the first few are 0, 1, 36, 1225, and 41616.
6 The International System of Units defines seven units of measure as a basic set from which all other SI units are derived. The SI base units and their physical quantities are: the meter for length, the kilogram for mass, the second for time, the ampere for electric current, the kelvin for temperature, the candela for luminous intensity, and the mole for the amount of substance.
7 These objects are the Sun, the Moon, and the five classical naked eye planets: Mars, Mercury, Jupiter, Venus, and Saturn.
8 “The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information” is one of the most highly cited papers in psychology. It was published in 1956 by the cognitive psychologist George A. Miller of Princeton University’s Department of Psychology in Psychological Review. It is often interpreted to argue that the number of objects an average human can hold in working memory is seven, plus or minus two. This is frequently referred to as Miller’s Law.
9 The four ‘scientific’ arts – music, arithmetic, geometry and astronomy (or astrology) – were known from the time of Boethius onwards as the Quadrivium; while after the ninth century the remaining three arts of the ‘humanities’ – grammar, rhetoric and logic - were classed as well as the Trivium. It was in that two-fold form that the seven liberal arts were studied in the medieval Western university. During the Middle Ages, logic gradually came to take predominance over the other parts of the Trivium. In the Renaissance, the Italian humanists and their Northern counterparts, despite in many respects continuing the traditions of the Middle Ages, reversed that process. Re-christening the old Trivium with a new and more ambitious name of law and medicine. The ideal of a liberal arts, or humanistic education grounded in classical languages and literature, persisted until the middle of the twentieth century.
10 During the Depression, the Commonwealth of Pennsylvania attempted to fund public works through passage of the Pennsylvania State Authority Act in 1936. The Act provided for the incorporation of the General State Authority, which would purchase land from the state and add improvements to that land using state loans and grants. The state expected to receive Federal grants and loans to fund the project under the administration of President Franklin D. Roosevelt and his New Deal. The Pennsylvania Supreme Court, in Kelly v Earle, found the Act violated the state constitution. This prevented the state from receiving federal funds for Works Progress Administration projects and making it difficult to lower the extremely high unemployment rate. Pennsylvania manufactured 6.6 percent of total United States military armaments produced during World War II, ranking sixth among the 48 states.
11 “An easier question to answer, he maintains, is the size of the average person’s vocabulary. He suggests taking a sample of about 20 or 30 pages from a medium-sized dictionary, one which contains about 100,000 entries or 1,000 to 1,500 pages. Tick off the ones you know and count them. Then multiply that by the number of pages and you will discover how many words you know. Most people vastly underestimate their total. ‘Most people know half the words - about 50,000 - easily. A reasonably educated person about 75,000 and a really cool, smart person well, maybe all of them but that is rather unusual. An ordinary person, one who has not been to university say, would know about 35,000 quite easily.’” -“The words in the mental cupboard,” BBC Magazine, April, 2009, quoting Professor David Crystal