Note that this is only one of an infinite number of ways that unit cells of space groups 10 and 13 can be related, particularly in relation to translation. For example: 10:a,b,c;0,0,0 > a-c,b,2c;0,0,5/2 > 13:a,b,c;0,0,1 adds a unit translation along the c axis. Symmetry equivalence aside, there are visualization contexts where we might want to emphasize some particular translation in this way.