code: function (firstEdge, secondEdge) {
  		if (firstEdge === Constants.SOLID && secondEdge === Constants.SOLID) {
  			return Constants.EMPTY;
  		}
  		
  		if (firstEdge === Constants.SOLID && secondEdge === Constants.EMPTY) {
  			return Constants.EMPTY;
  		}
  		
  		return firstEdge;
  	}
docs: Resolve the given flags of two shared tile boundary edges.
  
  Returns the new flag to use for the first edge after comparing it with
  the second edge.
  
  If both edges are solid, or the first is solid and second is empty, then
  the empty edge flag is returned. Otherwise the first edge is returned.
  
  This compares boundary edges of each tile, not polygon edges.
  
  @method Phaser.Plugin.ArcadeSlopes.TileSlopeFactory#compareBoundaryEdges
  @param  {int} firstEdge  - The edge to resolve.
  @param  {int} secondEdge - The edge to compare against.
  @return {int}            - The resolved edge.