The anisotropic growth of twinned platelets having a cubic crystal str
ucture is examined by a ball-model simulation of the growth process. T
he simulation has suggested that the long-accepted growth mechanism, w
hich relies on the self-regenerating {111} faceted-side-face structure
, may need revision. Such a side-face structure is likely to transform
into a different structure where the twin bands are bound by {100} pl
anes. Experimental evidence is presented to support this structure for
the silver halide system.