The B domain of ey has been replaced by the B domain of eyg.
eye | ectopic, with Scer\GAL4dpp.blk1
Expression of ey::eygEEEGEE.Scer\UAS, driven by Scer\GAL4dpp.blk1, induces ectopic eyes, but of smaller size than when wild-type ey is overexpressed.