Clones induced in the wing disc produce two types of abnormal wings: those of normal size and shape but with ectopic vein structures (reflecting the shortvein function of dpp), and those of abnormal size and shape with dramatic alterations of the normal pattern (when clones contributed to both dorsal and ventral surfaces). Cells in clones associated with reorganized anterior patterns behave like wild-type cells positioned close to vein 2 and organize surrounding tissue to form symmetric, more anterior patterns on either side. Clones positioned posterior to vein 5 cause reorganized posterior pattern including the formation of supernumerary double posterior wings. Ectopic dpp function can suffice to organize both posterior and anterior wing pattern even in the absence of endogenous dpp function.