using System;

public class Program

{

    public static void Main(string[] args)

    {

        var colours = new string[] {"red","green","purple","orange","lilac","red","green","purple","orange","lilac","red","green","purple","orange","lilac","red","green","purple","orange","lilac"};

        float durationS = 9;

        for (float i = 0; i < durationS; i = i + 0.1f)

        {

            var z = ExpoEaseOut(i, 0, colours.Length, durationS);

            Console.WriteLine(colours[(int)z] + " \t" + z);

        }

        Console.WriteLine("");

        for (float i = 0; i < durationS; i = i + 0.1f)

        {

            var z = CircEaseOut(i, 0, colours.Length, durationS);

            Console.WriteLine(colours[(int)z] + " \t" + z);

        }

    }

    // the following taken from https://gist.github.com/xanathar/735e17ac129a72a277ee

    /// <summary>

    /// Easing equation function for an exponential (2^t) easing out: 

    /// decelerating from zero velocity.

    /// </summary>

    /// <param name="t">Current time in seconds.</param>

    /// <param name="b">Starting value.</param>

    /// <param name="c">Final value.</param>

    /// <param name="d">Duration of animation.</param>

    /// <returns>The correct value.</returns>

    public static float ExpoEaseOut(float t, float b, float c, float d)

    {

        return (t == d) ? b + c : c * (-(float)Math.Pow(2, -10 * t / d) + 1) + b;

    }

​

    /// <summary>

    /// Easing equation function for a circular (sqrt(1-t^2)) easing in: 

    /// accelerating from zero velocity.

    /// </summary>

    /// <param name="t">Current time in seconds.</param>

    /// <param name="b">Starting value.</param>

    /// <param name="c">Final value.</param>

    /// <param name="d">Duration of animation.</param>

    /// <returns>The correct value.</returns>

    public static float CircEaseIn(float t, float b, float c, float d)

    {

        return -c * ((float)Math.Sqrt(1 - (t /= d) * t) - 1) + b;

    }

    /// <summary>

    /// Easing equation function for a circular (sqrt(1-t^2)) easing out: 

    /// decelerating from zero velocity.

    /// </summary>

    /// <param name="t">Current time in seconds.</param>

    /// <param name="b">Starting value.</param>

    /// <param name="c">Final value.</param>

    /// <param name="d">Duration of animation.</param>

    /// <returns>The correct value.</returns>

    public static float CircEaseOut(float t, float b, float c, float d)

    {

        return c * (float)Math.Sqrt(1 - (t = t / d - 1) * t) + b;

    }

}