The first rule, then, is, that no group ought to be so placed as to admit of its being moved without deranging other groups, or the adjoining walks or objects. In other words, every group ought to fit in to the precise situation where it is placed, without admitting of its being moved to the right or left, backwards or forwards, without deranging the effect of the whole of which it forms a part. To fit any given situation, its outline must coincide more or less with some other outline (fig. 72.); and not diverge or converge with that outline (fig. 73.) at random, or have no relation to it at all.