/// <summary>
        /// Checks if a tubing is straight or two-directional.
        /// </summary>
        /// <returns>True if the connector is straight.</returns>
        private bool IsConnectorStraight(IItem item)
        {
            var children = item.Children;

            var flanges = children.Where(i => i.GetType() == typeof(Flange));

            var elbows = children.Where(i => i.GetType() == typeof(Elbow)).Count();

            return !(AllElementsParallel(flanges) && elbows > 0);
        }

        /// <summary>
        /// Compares an IEnumerable of items and their orientation / direction.
        /// </summary>
        /// <param name="items">The items to compare.</param>
        /// <returns>True if all the elements are parallel.</returns>
        private bool AllElementsParallel(IEnumerable<IItem> items)
        {
            var distinctOrientations = items
                .ToList()
                .GroupBy(i => i.Orientation)
                .Select(g => g.First())
                .ToList();

            return distinctOrientations.Count > 1;
        }