Creates wavy text using Reddit's markup.

Program.cs

using System;
using System.Linq;
using System.Text;

namespace WavyText
{
    class Program
    {
        private enum Direction
        {
            Up,
            Down
        }

        private const int MAX_HEIGHT = 3;
        private const char CARAT = '^';

        static void Main(string[] args)
        {
            var input = args.Length > 0 ? args[0] : Console.ReadLine();
            var output = new StringBuilder();

            var direction = Direction.Up;
            var currentHeight = 0;

            foreach (var c in input)
            {
                if (c == ' ')
                {
                    output.Append(c);
                    continue;
                }

                output.Append(string.Join(string.Empty, Enumerable.Repeat(CARAT, currentHeight)));
                output.Append(c);
                output.Append(" ");

                if (currentHeight <= 0)
                    direction = Direction.Up;
                else if (currentHeight >= MAX_HEIGHT)
                    direction = Direction.Down;

                switch (direction)
                {
                    case Direction.Up:
                        ++currentHeight;
                        break;
                    case Direction.Down:
                        --currentHeight;
                        break;
                }
            }

            Console.WriteLine(output.ToString());

            Console.ReadKey(true);
        }
    }
}