The blind, next, previous and rewind allow more direct control over automated indexes from the DIML interface.
The back statement rewinds a vectorial or matricial structure one step back, fixing the associated automated indexes. If the target is a DIML vector, the index for dimension 1 variable-name§I is lowered by 1.
If the target is a matrix or any multidimensional array, the lowest index is concerned (variable-name§I§I...§I). If the target is "fully specified", reaching the end of the row will propagate index decrementation to the higher indexes.