  Let (W,S) be a Coxeter system of affine type D, and let TL(W) the
corresponding generalized Temperley-Lieb algebra. In this extended abstract we
define an infinite dimensional associative algebra made of decorated diagrams
which is isomorphic to TL(W). Moreover, we describe an explicit basis for such
an algebra of diagrams which is in bijective correspondence with the classical
monomial basis of TL(W), indexed by the fully commutative elements of W.
