Let Af represent a female of class A, and similarly Bm, Bf, &c.

Let Ap represent progeny who belong to class A, and similarly Bp, Cp,
Dp.

Law 2 may now be set down as under--

Af + Bm Am + Bf Cf + Dm Cm + Df
------- ------- ------- -------
Dp Cp Bp Ap

3. The first law holds good with the progeny of these combinations, i.e.,
Dp can only marry one of class C--though neither the father nor mother of
Dp could marry into class C; similarly for Cp, &c.

4. Dp recognises as father or mother all members of classes A and B;
similarly Cp, &c.

This explains the seeming absurdity of the answer one receives from
natives to questions concerning their relationships to others. An old man,
for instance, may point out a young girl and say, "That one my mother,"
for the girl belongs to the same class as his actual father or mother.

5. All the progeny of classes A and B are brothers and sisters; similarly
C and D.

Thus taking Dp2 to represent the progeny of an Ap and a Bp

Af + Bm Ap + Bp
--------- -------