What is an analogy for a smooth endoplasmic reticulum?

Endoplasmic reticulum (ER) is such as a manufacturing plant, like a factory, where proteins and lipids are made. This is also where things are packaged into boxed and sent off to dissimilar places. In the cell the smooth ER is a network of membrane bound bodies which be short of ribosome (the molecules used in protein synthesis) and its primary function is to change, encapsulate and transport newly synthesized proteins and lipids which will be secreted or remain in the cytoplasm as membrane bound vesicles.