Like the vocabulary of a language, the meanings of the basic dotplot features are preserved in many variations and combinations. Surprisingly, the meanings of the basic dotplot features are also preserved at different scales. Dotplots can be interpreted by recognizing the basic variations of visual features, understanding their meanings, and interpreting their meanings with respect to your data.

Squares & Diagonals
The basic visual features of Dotplots are squares and diagonals. On the left, squares are modeled 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 two squares indicate a change in vocabulary.

On the right, diagonals are modeled with a repeated character 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.

Shuffling
Squares may appear in different densities. On the left, some non-repeating tokens are shuffled into the second half of a sequence that creates two squares. The second square looks lighter because fewer tokens are matching. Any two sequences can be shuffled together. The pattern of shuffled squares and diagonals on the right identifies documents and their translations.