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.
The three-dimensional counterpart of a parallelogram is a parallelepiped. A quadrilateral with one pair of parallel sides is a trapezoid in American English or a trapezium in British English. The etymology (in Greek ÏÎ±ÏÎ±Î»Î»Î·Î»-ÏÎ³ÏÎ±Î¼Î¼Î¿Î½, a shape of parallel lines) reflects the definition.