The dotplots on this page are created from synthetic character sequences. Here characters are treated as tokens and a dot is plotted where characters match.

Squares are formed by a sorted sequence of a's and b's. The a's match each other, but not the b's, and vice versa. In general, one square indicates a high density of unordered matches, usually due to common vocabulary, while multiple squares indicate a change in vocabulary.

Diagonals are formed by a repeated sequence. In general, diagonals indicate ordered matches such as copies or versions. Diagonals indicate that two sub-sequences have a significant number of words in common, but unlike squares, the common words occur in the same order.

In general squares and diagonals represent unordered and ordered matches, respectively. The entire spectrum of dotplot similarity patterns may be understood in terms of variations and combinations of squares and diagonals.

Broken diagonals indicate the insertion of tokens into what would otherwise be perfect copies. The breaks indicate exactly where the changes have been made. When comparing two versions of a document or a source-code file, the breaks in the diagonals indicate exactly where new material has been added.

When reordering patterns appear when looking at multiple versions of documents or code it often indicates that filenames have been changed between versions, changing the relative order in which the files are being compared.

Any two sequences may be shuffled together. A pattern of shuffled squares and diagonals identifies documents and their translations.