15 lines

let colors = [
   230,229,15
   243,209,0
   246,132,0
   239,55,1
   219,29,3
   194,8,83
   117,26,123
   56,24,100
   43,38,161
   2,98,208
   0,153,179
   0,174,66
   39,185,22
   103,196,2
   173,214,0]

#r "System.Drawing.dll"
open System.Drawing

let brushes =
   colors |> List.map (fun (r,g,b) -> new SolidBrush(Color.FromArgb(255,r,g,b)) )

let xs = [3;2;1;4;2;1;4;2;1;4;2;1;4;2;1]
let ys = [0;10;14;8;11;6;9;4;7;2;5;12;4;13;1]
let width,height=476,450
let w,h = 14,30

let draw k =
   let image = new Bitmap(width,height)
   use graphics = Graphics.FromImage(image)
   for y = 0 to 14 do
      List.zip xs ys
      |> List.mapi (fun i xy -> i,xy)
      |> List.scan (fun x (i,(dx,dy)) ->
         let k = if i%2 = 0 then -k else k
         let brush = brushes.[(15+(y + dy+k))%15]
         graphics.FillRectangle(brush, x*w, y*h, w*dx,h)
         x + dx
      ) 0 |> ignore
   image

(*
#r "System.Windows.Forms.dll"
open System.Windows.Forms

let show () =
   let image = draw ()
   let form = new Form (Text="15", Width=width+16, Height=height+36)
   let picture = new PictureBox(Dock=DockStyle.Fill, Image=image)
   do  form.Controls.Add(picture)
   form.ShowDialog() |> ignore

show()
*)

#r @"Gif.Components.dll"

open Gif.Components

let encoder = AnimatedGifEncoder()
if encoder.Start(@"c:\app\15.gif") then
   encoder.SetFrameRate(2.0f)
   encoder.SetRepeat(0)
   for i = 0 to 15 do
      encoder.AddFrame(draw i) |> ignore
   encoder.Finish() |> ignore