  We consider algebras $e_i \Pi^\lambda(Q) e_i$ obtained from deformed
preprojective algebra of affine type $\Pi^\lambda(Q)$ and an idempotent $e_i$
for certain concrete value of the vector $\lambda$ which corresponds to the
traces of $-1\in SU(2, C)$ in irreducible representations of finite subgroups
of $SU(2, C)$. We give a certain realization of these algebras which allows us
to construct the $C^*$-enveloping algebras for them. Some well-known results,
including description of four projections with sum 2 happen to be a particular
case of this picture.
