Betza's funny notation ones. The notation is based on dividing moves that can be made on a board of squares into groups of symmetry-equivalent moves, the moves within a group differing only in the direction in which the step is taken. Each such group (referred to as "atom") is indicated by a capital, such as N for the 8 moves of the knight. The letter that represents the atom is usually the first letter of the simplest piece from current or historic chess variants that has this move, such as A and F for the alfil and ferz of shatranj (ancient Arabic/Persian chess).
The Missing Piece (book) it begins to realize that it can no longer do the things it used to enjoy doing, like singing or rolling slowly enough to enjoy the company of a worm or butterfly. It decides that it was happier when searching for the missing piece than actually having it. So it gently puts the piece down, and continues searching happily. A sequel was published in 1981 entitled "The Missing Piece Meets The Big O", which is told from a Missing Piece's point of view. The Missing Piece (book) The Missing Piece is a children's picture book by poet Shel Silverstein. The