If you move one star tile (any color) into two others, you create a star cluster. An area of the tiles will disappear and new ones fall down. Drawback is that you do not know the direction or circle of the area that will disappear. Great in latter part of game where there is no play in area to create a star.
Bombs will disappear in a star cluster, but you can not judge the radius. In example above I could have gotten rid of bomb by moving it into the red star tiles (all red on board would be gone). I moved the star into a cluster to see the radius of disappearance. Also knew if bomb not included in radius, it would drop near two lower red tiles and not ruin my game. Turns out the bomb was not in the radius.
