SpiroGifsCreates the frames of a [Spirograph](http://en.wikipedia.org/wiki/Spirograph) animation. Modify the variables in lines 12-22 for various patterns. After stitching the resulting images into a gif, they look like this: http://imgur.com/FPrWHOw, http://imgur.com/pFeMozI

SpiroGifs.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Drawing;

namespace SpiroGifs
{
    class Program
    {
        const int BmpWidth = 300;
        const int BmpHeight = 300;
        List<PointF> pointlist = new List<PointF>();

        List<List<PointF>> ppl = new List<List<PointF>>();
        const int numppl = 11;
        bool drawfluff = false;
        float R = 150;
        float r = 110;
        float g = 60;
        const int numFrames = 100;
        const float FrameRate = 9F;

        static void Main(string[] args)
        {
            Program p = new Program();
            for (int i = 0; i < numppl; i++)
            {
                p.ppl.Add(new List<PointF>());
            }

            for (int i = 0; i < numFrames; i++)
            {
                p.drawFrame(i);
            }
        }

        void drawFrame(int i)
        {
            Bitmap bmp = new Bitmap(BmpWidth, BmpHeight);
            using (Graphics context = Graphics.FromImage(bmp)){
                context.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
                context.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                context.Clear(Color.CornflowerBlue);

                float alpha = i / FrameRate;

                Pen p = Pens.Beige;

                if (drawfluff)
                {
                    context.DrawEllipse(p, getBoundingRectForEllipse(0, 0, R));
                    context.DrawEllipse(p, getBoundingRectForEllipse((R-r)*cosf(alpha), (R-r)*sinf(alpha), r));
                }


                for (int k = 0; k < numppl; k++)
                {
                    float theta = alpha + k * (numFrames / FrameRate);
                    float x = (R - r) * cosf(theta) + g * cosf(theta * (1 - R / r));
                    float y = (R - r) * sinf(theta) + g * sinf(theta * (1 - R / r));
                    //pointlist.Add(new PointF(tx(x), ty(y)));
                    ppl[k].Add(new PointF(tx(x), ty(y)));
                    for (int j = 1; j < ppl[k].Count; j++)
                    {
                        context.DrawLine(p, ppl[k][j - 1], ppl[k][j]);
                    }
                }

            }

            bmp.Save(string.Format("foo{0:000}.png", i), System.Drawing.Imaging.ImageFormat.Png);
        }

        float cosf(float theta)
        {
            return (float)Math.Cos(theta);
        }

        float sinf(float theta)
        {
            return (float)Math.Sin(theta);
        }

        RectangleF getBoundingRectForEllipse(float x, float y, float r)
        {
            return new RectangleF(
                tx(x) - r,
                ty(y) - r,
                2 * r,
                2 * r);
        }

        float tx(float x) { return x + BmpWidth / 2; }
        float ty(float y) { return BmpHeight / 2 + y; }
    }
}