This is the 3 dimensional version of tic tac toe (4x4x4).
You have 4 layers each of rows and 4 columns.
You can get 4 in a row (and win) by 4 in a row (row, column or diagonal) in any of the layers or crossing layers. So, the top left hand corner of each layer would make 4 in a row.
This has different levels, although unlike the 2D version you can win against the best defence if you go first, but it is hard!
Multiple undo is available throughout the game both for correcting "fat finger" errors and for exploring
You can ask for the strong engine's suggestion via the "hint" button.
Because the 3D nature of the game makes it difficult to both squeeze the display into the viewing area and sometimes potential winning lines which cross levels can be difficult visualize there are several options for changing the display.
There is a "flip" button which will rotate the display through 120 degrees, changing the orientation to sometimes make lines more clear.
There are two sliders for changing the size and positioning of the four layers.
There are 4 buttons which make in turn each layer the top one on the display (so you can make a move on that layer if it is partially obscured by another). Note this doesn't change the layer's logical position, i.e. if you make the second layer the top visible layer it is still the second layer in the game.
First WP8 version. Also some minor fixes