gistfile1.cs

using System;
using System.Collections.Generic;
using System.Linq;

namespace ConsoleApplication2
{
    class Program {
        static void Main(string[] args) {

            var foo = new List<ISupport>();
            foo.Add(new FlatPoint());

            draw_Supports(foo);

        }


        public static void draw_Supports(IList<ISupport> supports) {

            foreach (var item in supports) {
                Console.WriteLine(item.DoSomething());
            }
            
            Console.ReadKey();
        
        }

    }

    public interface ISupport {
        string DoSomething();
    }

    public class FlatPoint : ISupport {

        public string DoSomething() {
            return "Works!";
        }
    }
}