An architect is a person who plans, designs, and oversees the construction of buildings. To practice architecture means to provide services in connection with the design and construction of buildings and the space within the site surrounding the buildings, that have as their principal purpose human occupancy or use. It is suggested that various developments in technology and mathematics allowed the development of the professional [I]gentleman[/I] architect, separate from the hands-on craftsman. The availability of paper and pencils allowed pre-construction drawings to be made by professionals. Concurrently, the introduction of linear perspective and innovations such as the use of different projections to describe a three-dimensional building in two dimensions, together with an increased understanding of dimensional accuracy, helped building designers communicate their ideas.