  Current experiments on different samples of twisted bilayer graphene (TBG)
have found different sets of insulating phases. Despite this diversity, many
features of these insulating phases appear to be universal. They include the
dispersion of Landau fans away from charge neutrality, a reduced Landau fan
degeneracy from the expected value at charge neutrality, and the further
reduction of this degeneracy when crossing an insulating phase with odd number
of electrons in the superlattice unit cell. We point out that all these
behaviors as well as the ferromagnetic behavior observed in some of the
insulating states suggest an underlying "ideal" pattern, with different part of
it realized in the different samples in different experiments. We further show
that such pattern can be accounted for by a Hubbard like model for the
superlattice augmented with a set of chemical potential dependent mean fields
that break the symmetry of the eight internal degrees of freedoms successively.
The simultaneous importance of Mott like physics and mean field physics may be
a general feature of twisted 2D electronic materials with large superlattices,
not necessarily confined to graphene.
