Cavity and solid walls. 1  A cavity wall is made up of two walls with a gap in between, known as the cavity; the outer leaf is usually made of brick, and the inner layer of brick or concrete block.  A solid wall has no cavity; each wall is a single solid wall, usually made of brick or stone.
A cladogram (from Greek clados branch and gramma character) is a diagram used in cladistics which shows relations among organisms.
A Parallelogram is a four-sided shape with opposite sides that are both parallel and equal in length. The area of a parallelogram is the base times the height. A Trapezoid is a four-sided shape with at least one set of parallel sides. The area of a trapezoid is the average of the bases times the height.