private void AddAdjacentPixelsOnY(ICollection <MapPixel> adjacentPixels, ITwoDimensionalCoordinate coordinate) { var currentCoordinate = new MapCoordinate(coordinate.GetX(), coordinate.GetY()); for (var yOff = -1; yOff <= 1; yOff += 2) { currentCoordinate.SetY(coordinate.GetY() + yOff); if (CoordinateIsInBounds(coordinate)) { adjacentPixels.Add(_map[currentCoordinate.GetX(), currentCoordinate.GetY()]); } } }