- Johann Nikolaus Forkel (22 February 1749 – 20 March 1818) was a German musicologist and music theorist, generally regarded as among the founders of modern musicology. His publications include Johann Sebastian Bach: His Life, Art, and Work, the first substantial survey on the life and works of Johann Sebastian Bach.
- Triangle (Wikipedia)
A triangle is a polygon with three edges and three vertices. It is one of the basic shapes in geometry. A triangle with vertices A, B, and C is denoted △ABC.