Jones describes two "rules" (p.24 and p.17, capitalization his):
The Unit of Time Rule or the Rule of Twos and Threes: "African [Ewe] phrases are built up of the numbers 2 or 3, or their multiples: or of a combination of 2 and 3 or of the multiples of this combination. Thus a phrase of 10 will be (2 + 3) + (2 + 3) or (2 + 2 + 2) + 4.
The Rule of Repeats: "The repeats within an African [Ewe] song are an integral part of it." If a song is formally "A + A + B + B + B" one cannot leave out, say, one of the B sections.
He also lists the following "Features of African [Ewe] Music" (p. 49):
"Songs appear to be in free rhythm but most of them have a fixed time-background.
The rule of 2 and 3 in the metrical build of songs.
Nearly all rhythms which are used in combination are made from simple aggregates of a basic time-unit. A quaver is always a quaver.
The claps or other time-background impart no accent what-ever to the song.
African [Ewe] melodies are additive: their time-background is divisive.
The teleological trend: many African [Ewe] songs lean towards the ends of the lines: it is at the ends where they are likely to coincide with their time-background.
Gankogui, axatse, and atoke. The Gankogui is a clapperless double bell that is pounded in shape rather than cast. It produces much less audible high partials than western bells ("purer" fundamental) and is played with a stick. It produces two notes each of which vary and must vary among gankogui so they may be used together. Axatse are rattles, and the atoke are high pitched gongs played with an iron rod. The gankogui plays a background pattern which the orchestra builds upon, though the tempo is set by the master drummer. Many patterns from 8-12 beats are used but the decidedly most common pattern is called the Standard Pattern: