Suppes considers two basic operations: the operation \(B\), that corresponds with bisecting a line \(ab\) and the operation \(D\), that corresponds with doubling a line \(ab\). A step \(C_{i}\) in a construction consists of three elements: the first element is the (new) point to be constructed, the second element is a pair of points that are already present, and the third element is either \(B\) or \(D\), according to what operation is selected. The starting position consists of three given points, \(a, b\), and \(c\).