public static void DrawMarker(this KalikoImage ki, Point p, Color col, int radius = 1)
        {
            List <Point> points = new List <Point>();

            for (int j = -radius; j < radius; ++j)
            {
                for (int i = -radius; i < radius; ++i)
                {
                    int x = p.X + i;
                    int y = p.Y + j;
                    if (ki.IsPointCorrect(x, y))
                    {
                        points.Add(new Point(x, y));
                    }
                }
            }

            SetPixels(ki, points, col);
        }