LCD numbers kata (C#)

LCD.cs

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

namespace ViveCodigo.Katas.LCD
{
    /// <summary>
	/// Basado en la idea original de @rodrigo_salado
    /// </summary>
    public class LCD
    {
        /// <summary>
        /// Diccionario que define los diferentes símbolos para pintar los números.
        /// </summary>
        private static readonly Dictionary<int, string> Leds = 
			new Dictionary<int, string>
			   {
				   {0, "   "},
				   {1, " _ "},
				   {2, "| |"},
				   {3, "|_|"},
				   {5, " _|"},
				   {6, "|_ "},
				   {7, "  |"},
				   {8, "|  "},
			   };

        /// <summary>
        /// Diccionario que define los diferentes dígitos disponibles.
        /// </summary>
        private static readonly Dictionary<char, LCD> Digitos = 
			new Dictionary<char, LCD>
			   {
				   {'0', new LCD(1, 2, 3)},
				   {'1', new LCD(0, 7, 7)},
				   {'2', new LCD(1, 5, 6)},
				   {'3', new LCD(1, 5, 5)},
				   {'4', new LCD(0, 3, 7)},
				   {'5', new LCD(1, 6, 5)},
				   {'6', new LCD(1, 6, 3)},
				   {'7', new LCD(1, 7, 7)},
				   {'8', new LCD(1, 3, 3)},
				   {'9', new LCD(1, 3, 5)}
			   };

        /// <summary>
        /// Arreglo que contiene la representación de cadena del dígito.
        /// </summary>
        private readonly string[] filas;

        private LCD(int top, int mid, int bot) : 
			this(new[] {Leds[top], Leds[mid], Leds[bot]}) {}

        private LCD(string[] filas)
        {
            this.filas = filas;
        }

        private LCD()
        {
            filas = new[] { "", "", "" };
        }

        public override string ToString()
        {
            return string.Join("\n", filas);
        }

        public static LCD operator +(LCD a, LCD b)
        {
            return new LCD(a.filas.Select((t, i) => t + b.filas[i]).ToArray());
        }

        public static string ToLCD(int numero)
        {
            var result = new LCD();
            foreach (var digito in numero.ToString())
            {
                result += Digitos[digito];
            }
            return result.ToString();
        }
    }
}