  Symbiotic Miras give a nice practical demonstration of the formation of
bipolar and highly aspherical nebulae as a consequence of interaction in
detached binaries. We believe that these binary systems are among the most
promising candidates for the progenitors of bipolar planetary nebulae. We
present a list of the optically extended nebulae known to date around symbiotic
Miras, and illustrate their properties using recent HST and ESO-NTT [NII]
images of He 2-104 and He 2-147.
