Dialhex

Gameplay 

Part of Nintendo's Japanese-only Bit Generations series for the Game Boy Advance, Dialhex is a color matching puzzle game.  You control a cursor that looks like a hexagon over a game board which also looks like a hexagon.  The hexagon can spin, and when it does, any of the triangular shaped pieces underneath will move in a circle.  When you get all of the triangles in the hexagon to match, those six pieces will disappear.  Throughout gameplay more triangle pieces are added by falling from above at increasing speeds.
 

Special Pieces

Along with the eight colored pieces are black and white triangle pieces.  White pieces added to a hexagon will eliminate all of that color it is joined with on the entire game board.  For example, a hexagon with a white piece and five orange pieces will eliminate every orange piece on the board.  Black pieces will create a "funnel" at the bottom of the board and a number of pieces will fall out.
 

Modes 

Solo Mode:   You only start with two different colors, and after creating six of each single-color hexagon, another color will be added.  The cycle continues until there are eight colors.    
 
Endless Mode:  Gameplay does not stop until the screen is filled up with pieces and no more can fall down into the play area.  This mode is unlocked by completing solo mode. 
 
Vs. Mode:  A two player mode requiring two Game Boy Advance systems, two copies of Dialhex, and a link cable.  Each player gets half of the board, and matching pieces will cause additional pieces or useless "junk" pieces to fall onto the other player's side.

North American Release

Although not available for Game Boy Advance, the game was released as Art Style: ROTOHEX for Nintendo's WiiWare service in North America. 
 

Language

Although Dialhex is a Japan only release, the game is completely in English.  The manual, however, is not.