Interfaces in Object Oriented Programming Languages. An interface is a programming structure/syntax that allows the computer to enforce certain properties on an object (class). For example, say we have a car class and a scooter class and a truck class. Each of these three classes should have a start_engine() action.
The epidermis is the very outer layer of the skin that provides protection from bacteria (thanks to it's pH level), becoming overloaded with water (it's waterproof) and from heat loss. It has four of five distinct layers to achieve this.
Epidermis: Top layer of our skin, is covered with the stratum corneum, which consists of several layers of dead cells, which protect the layers below. New cells of the epidermis are made at the border between dermis and epidermis and travel upwards (actually the top layers are worn off).