Twiny is a small Fortran program for identification or confirmation of the twin element from the morphological analysis of twins. It takes as input the twin element and computes the angle between corresponding [uvw] directions in two individuals of the twin: the result can be used by the investigator to confirm or invalidate the supposed twin element. Twiny also accepts as input the angle measured on the sample and computes all possible twin elements compatible with this angle: the result helps the investigator to identify the twin element before any attempt to unravel the diffraction pattern of a twin.