article: Generating a Seamless Tiling of a Nature Image, by Budi Hartanto

Virtual vertical, and horizontal, lines in a tiling are called ‘seams’, and this article discusses a method for eliminating them. (Reminds me of adjusting the text of a document so as to eliminate ‘rivers’ in the document.)
Here is the link to the article.
And here is the link to the citation (with abstract) of the article.
keywords: tessellation, virtual vertical lines, virtual horizontal lines, smoothing, visual aesthetics, visual appeal, source image, divided into fractions, seamless tiling algorithm, continuity