You have to form vertical or horizontal lines of three or more identical pebbles. Two adjacent pebbles may be swapped only if one or both of them form a line of three or more identical pebbles. A clue is shown if you don't find any combination after 5 seconds. It helps a lot at the beginning... but only at the beginning !
Careful, your brain may explode !
AEGIDIAN I don't feel this is crap, or a rip-off of Jeweltoy. For any gameplay idea, there can be any number of implementations this is one, Jeweltoy is another. (Version 1.1)