Types of two-dimensional pendulums and their uses in education
Pendulums which swing in two dimensions simultaneously and are designed to leave a record of their motion are termed 'harmonographs'. The curves which they draw are known, alternatively, as 'Bowditch curves' or 'Lissajous curves'. A variety of designs of harmonographs have been invented over the years. These may be a 'Y-suspended' 'simple' pendulum, or they may be a complex 'physical' pendulum system. Harmonographs have been built as demonstration apparatus in physics (or mathematics) or as 'art' machines for enjoying the aesthetics of the curves produced.
Physics, Astronomy, and Materials Science
Whitaker, Robert J. "Types of two-dimensional pendulums and their uses in education." Science & Education 13, no. 4 (2004): 401-415.
Science and Education