however it seems pretty hard to manually make the beautiful pattern you showed on the picture :) 

After trying for a few minutes, mostly I get "not-too-aesthetic" patterns like this one:

I wonder if it is possible to make algoritm always generate "perfect" (aesthetically pleasing) pattern? :)

Thanks for testing it.

As you can see, there are different styles of patterns to create a lot of variations in compositions.

I possibly could group patterns limiting possibilities, or surrounding some patterns with a yellow stroke to say ("add me too"), but i thought it was better to let users take choices, find combinations i wouldn't have think of or even upload patterns that can mix with 2 elements.  Or only play with drag'n dropping one or several images.

Choosing only one (or 2 patterns near in similarity) assure you to an aeshetically pleasing compo.

By the way, patterns are already kind of grouped on lines in the GUI (flat filled geometric figures, lines, hatch, round lines with light stroke, round lines with heavy stroke, triangles, rounds,...), try 2 or 3 patterns next to each others in a line. Some patterns work great alone, others in combination.

Makio135
http://makio135.com/