The Graph unit (GRAPH.TPU) implements a complete library of over 50 graphics routines that range from bit-oriented routines to high-level calls.
To compile a program that uses the Graph unit, you don't need any external files. (Of course, you'll need your program's source code, the compiler, and access to the standard units in TURBO.TPL).
To run a program that uses the Graph unit, you'll need one (or more) of the graphics drivers (.BGI files) in addition to your .EXE program. If your program uses any stroked fonts, you'll need one or more font (.CHR) files.