static readonly double  M_PI = 3.14159265358979323846;

Cairo.Graphics gr;
/* initialize gr */

/* draw an arc with a color */
gr.Color = new Color (1,0.2,0.2, 0.6);
gr.Arc (0.04, 0.53, 0.02, 0, 2*M_PI);
gr.Arc (0.27, 0.65, 0.02, 0, 2*M_PI);
gr.Fill ();