A magic square is a series of numbers arranged in the form of a
square in which horizontal, diagonal and vertical rows add up to
the same total. Magical talismans have been used by Abramelin,
Aleister Crowley, Cornelius Agrippa and Dr John Dee. Yantras are
Indian magic squares which are a form of mandala - they are usually
constructed for meditational purposes - astrological yantras are
used when the additional energy from any of the planets is
required.