Perspective (graphical) on the horizon line. All lines parallel with the viewer's line of sight recede to the horizon towards this vanishing point. This is the standard "receding railroad tracks" phenomenon. A two-point drawing would have lines parallel to two different angles. Any number of vanishing points are possible in a drawing, one for each set of parallel lines that are at an angle relative to the plane of the drawing. Perspectives consisting of many parallel lines are observed most often when drawing architecture (architecture frequently uses lines parallel to the x, y, and z axes). Because it is rare to have
Point-to-point construction designed operating procedures. An intermediate form of point-to-point construction uses terminal strips (sometimes called "tag boards") or turret boards. The crucial invention was to apply soldering to electrical assembly. In soldering, an alloy of tin and lead, or later bismuth and tin, is melted and adheres to other, nonmolten metals, such as copper or tinned steel. Solder makes a strong electrical and mechanical connection. Note that if components are arranged on boards with tags or turrets at both ends and wires going to the next components, then the construction is correctly called tag or turret construction respectively, as the components