function Tile(position,value){this.x=position.x;this.y=position.y;this.value=value||2;this.previousPosition=null;this.mergedFrom=null;}
Tile.prototype.savePosition=function(){this.previousPosition={x:this.x,y:this.y};};Tile.prototype.updatePosition=function(position){this.x=position.x;this.y=position.y;};Tile.prototype.serialize=function(){return{position:{x:this.x,y:this.y},value:this.value};};