The use of a simple dot matrix

In these comparisons, a diagonal line indicates sequence similarity. (a) The word BIOLOGY is compared with itself. Dots are placed where the same letter occurs at the two corresponding positions. Notice the diagonal line that is formed. (b) Two similar but different sequences, BIOLOGY and ECOLOGY are compared with each other. Notice that only a partial line is formed by this comparison. Clearly the two terms are related (the suffix logy is the study of a particular topic determined by the initial word stem) but are not identical.