Bond-line Notation of organic compounds

Occasionally, the bonds in between carbon atoms are denoted by lines. For instance, n-hexane has a continuous chain of six carbon atoms that may be denoted as,

In this notation, the carbon atoms are denoted by line ends and intersections. It is supposed that the required numbers of hydrogen atoms are present where they are essential to satisfy the tetravalency of carbon. A single line denotes a single bond (C - C), two parallel lines denote a double bond (C = C) and three parallel lines denote a triple bond (C Ξ C). For instance,