Examples of two spatially interacting subsequences. (a) More specifically, GL8 motif representative pattern (left) interacts with TG9 (right). Both patterns are coloured in blue. Red spheres representing natural variants causing nephrogenic diabetes insipidus (NDI). If we look at these patterns, it is not important to know which pattern position is involved in a spatial interaction. It is more important, that these two pattern build an interacting block. (b) The corresponding interaction block scheme (IBS), with the interacting pattern in blue letters. Red letters illustrating positions causing NDI. All patterns have variable positions. These positions are marked with X. Different coloured bubbles are present and address an X-position with possible natural variants. These are examples of possible occupations, which can be realized by natural variants derived from known structures (blue), natural variants causing NDI (red), or new natural variants derived from unknown structures (green).