designPatternGuru/DesignPatternGuru/AbstractFactory/Products/ConcreteProductB1.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace AbstractFactory.Products
{
	internal class ConcreteProductB1 : IAbstractProductB
	{
		public string AnotherUsefulFunctionB(IAbstractProductA collaborator)
		{
			var result = collaborator.UsefulFunctionA();

			return $"The result of the B1 collaborating with the ({result})";
		}

		public string UsefulFuctionB()
		{
			return "The result of the product B1.";
		}
	}
}