RosettaCodeData/Task/2048/00-TASK.txt

;Task:
Implement a 2D sliding block puzzle game where blocks with numbers are combined to add their values.


;Rules of the game:
:*   The rules are that on each turn the player must choose a direction   (up, down, left or right).
:*   All tiles move as far as possible in that direction, some move more than others. 
:*   Two adjacent tiles (in that direction only) with matching numbers combine into one bearing the sum of those numbers. 
:*   A move is valid when at least one tile can be moved, including by combination. 
:*   A new tile is spawned at the end of each turn at a randomly chosen empty square   (if there is one). 
:*   Most of the time, a new '''2''' is to be added, but occasionally ('''10%''' of the time), a '''4'''.
:*   To win, the player must create a tile with the number '''2048'''. 
:*   The player loses if no valid moves are possible.


The name comes from the popular open-source implementation of this game mechanic, [https://gabrielecirulli.github.io/2048/ 2048].


;Requirements:
* &nbsp; "Non-greedy" movement.<br>&nbsp; The tiles that were created by combining other tiles should not be combined again during the same turn (move).<br>&nbsp; That is to say, that moving the tile row of:

               <big><big> [2][2][2][2] </big></big>

:: to the right should result in: 

               <big><big> ......[4][4] </big></big>

:: and not:

               <big><big> .........[8] </big></big>

* &nbsp; "Move direction priority".<br>&nbsp; If more than one variant of combining is possible, move direction shall indicate which combination will take effect. <br>&nbsp; For example, moving the tile row of:

               <big><big> ...[2][2][2] </big></big>

:: to the right should result in:

               <big><big> ......[2][4] </big></big>

:: and not:

               <big><big> ......[4][2] </big></big>



* &nbsp; Check for valid moves. The player shouldn't be able to gain new tile by trying a move that doesn't change the board.
* &nbsp; Check for a win condition.
* &nbsp; Check for a lose condition.
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