(the antae), and two columns placed between them. A door allows the to be accessed from the . A similar room at the back of the is called the opisthodomos. There is no door connecting the with the ; its existence is necessitated entirely by aesthetic considerations: to maintain the consistency of the peripteral temple and to ensure its visibility from all sides, the execution of the front has to be repeated at the rear. A restricted space, the , may be included at the far end of the , backing up on the . The complex formed by the , , and possibly the is enclosed on all four sides by the peristasis, usually a single row, rarely a double one, of columns. This produces a surrounding colonnade, the pteron, which offered shelter to visitors of the sanctuary and room for cult processions. Plan types These components allowed the realisation of a variety of different plan types in Greek temple architecture. The simplest example of a Greek temple is the , a small rectangular structure sheltering the cult statue. In front of the , a small porch or was formed by the protruding walls, the antae. The was linked to the by a door. To support the superstructure, two columns were placed between the (distyle in antis). When equipped with an opisthodomos with a similar design, this is called a double temple. A variant of that type has the at the back of the indicated merely by half-columns and shortened , so that it can be described as a . If the porch of a temple has a row of usually four or six columns in front of its whole breadth, the temple is described as a or prostyle temples. The whole may be omitted in this case or just leave the without columns. An amphiprostylos or amphiprostyle repeats the same column setting at the back. In contrast, the term peripteros or peripteral designates a temple surrounded by ptera (colonnades) on all four sides, each usually formed by a single row of columns. This produces an unobstructed surrounding portico, the peristasis, on all four sides of the temple. A Hellenistic and Roman form of this shape is the pseudoperipteros, where the side columns of the are indicated only by engaged columns or pilasters directly attached to the external walls. A or dipteral is equipped with a double colonnade on