  A two-parameter group element is presented that interpolates between M-brane
solutions. The group element is used to interpret a number of exotic branes
related to the generators of the adjoint representation of E11 as non-marginal
half-BPS bound states of M-branes. It is conjectured that the adjoint
representation of E11 contains only generators related to bound states of
fundamental M-branes which, in the limit, may be understood as membrane
molecules.
