  We show how to "interleave" the monad for operads and the monad for
contractions on the category \coll of collections, to construct the monad for
the operads-with-contraction of Leinster. We first decompose the adjunction for
operads and the adjunction for contractions into a chain of adjunctions each of
which acts on only one dimension of the underlying globular sets at a time. We
then exhibit mutual stability conditions that enable us to alternate the
dimension-by-dimension free functors. Hence we give an explicit construction of
a left adjoint for the forgetful functor $\owc \lra \coll$, from the category
of operads-with-contraction to the category of collections. By applying this to
the initial (empty) collection, we obtain explicitly an initial
operad-with-contraction, whose algebras are by definition the weak
$\omega$-categories of Leinster.
