The building is part of the power too. The above drawing, of course, is schematic. It is an array of wells being pumped by a central power. Many more wells than shown could be pumped by the two eccentrics on the power. Each eccentric has 18 holes to which rod lines can be fastened.
Some installations have the powers mounted in the same building with the engine.
The rod lines would then come out through holes in the walls. The eccentric is really the essential element of the power. You probably think of something odd or behaving in a strange way when you read or hear the word eccentric. Actually, the eccentric in a power is, in fact, odd. It is fixed out of center to a revolving shaft.