Periodic table
The organization of the periodic table can be used to derive relationships between the various element properties, and also to predict chemical properties and behaviours of undiscovered or newly synthesized elements. Russian chemist Dmitri Mendeleev published the first recognizable periodic table in 1869, developed mainly to illustrate periodic trends of the then-known elements. He also predicted some properties of unidentified elements that were expected to fill gaps within the table. Most of his forecasts proved to be correct. Mendeleev's idea has been slowly expanded and refined with the discovery or synthesis of further new elements and the development of new theoretical models to explain chemical behaviour. The modern periodic table now provides a useful framework for analyzing chemical reactions, and continues to be widely used in chemistry, nuclear physics and other sciences.
Tabula (game)
According to the "Etymologiae" by Isidore of Seville, tabula was first invented by a Greek soldier of the Trojan War named Alea. The earliest description of "τάβλι" (tavli) is in an epigram of Byzantine emperor Zeno (r. 474–475; 476–491), given by Agathias of Myrine (6th century AD), who describes a game in which Zeno goes from a strong position to a very weak one after an unfortunate dice roll. The rules of Tabula were reconstructed in the 19th century by Becq de Fouquières based upon this epigram. The game was played on a board nearly identical to a modern backgammon board with 24 points, 12 on each side. Two players had 15 pieces each, and moved them in opposing directions around the board, according to the roll of three dice. A piece resting alone in a space on the board was vulnerable to being hit. Hitting a blot, reentering a piece from the bar, and bearing off, all had the same rules as today. The only differences with modern backgammon were the use of an extra die (three rather than two) and the starting of all pieces off the board (with them entering in the same way that pieces on the bar enter in modern backgammon).