  We introduce a new class of symmetric algebras, which we call hybrid
algebras. This class contains on one extreme Brauer graph algebras, and on the
other extreme general weighted surface algebras. We show that hybrid algebras
are precisely the blocks of idempotent algebras of weighted surface algebras,
up to socle deformations. More generally, for tame symmetric algebras whose
Gabriel quiver is 2-regular, we show that the tree class of an Auslander-Reiten
component is Dynkin or Euclidean or one of the infinite tress $A_{\infty}$,
$A_{\infty}^{\infty}$, or $D_{\infty}$.
