There is a tendency to utilize underground space for the less ornamental purposes of civilization; there is the Metropolitan Railway in London, for instance, there are new electric railways, there are subways, there are underground workrooms and restaurants, and they increase and multiply.
Polystyrene can be naturally transparent, but can be colored with colorants. Uses include protective packaging (such as packing peanuts and CD and DVD cases), containers (such as clamshells), lids, bottles, trays, tumblers, and disposable cutlery.
There are two common types of polystyrene foam: extruded polystyrene (popularly known by its Dow trademark, StyrofoamÂ®) and expanded polystyrene (EPS). Most food service applications, including meat trays, egg cartons, hamburger clam shells, foam plates and trays, are extruded polystyrene. However, the common coffee cup is expanded polystyrene as is almost all industrial cushion packaging. This is the cellular white molded foam that is used to package televisions, stereos, computers, delicate electronic equipment and other fragile industrial and consumer products. Both expanded polystyrene (EPS) and extruded polystyrene are used extensively as thermal insulation in industrial, commercial and residential construction.