// calculate the delta angle
        double dangle = 2.0 * PI / (NVERTICES - 1);        
        // set radius to be 3
        double r = 3;
        double a, b, c;
        a = b = c = r;

	    for(int i=0;i<NVERTICES;i++)
        {
            // caculate cos phi
            double cosphi = cos(dangle * i);
            // caculate sin phi
            double sinphi = sin(dangle * i);
		    for (int j=0;j<NVERTICES;j++)
		    {
                // calculate cos theta
                // calculate sin theta
                double costheta = cos(dangle * j);
                double sintheta = sin(dangle * j);
			    mesh[i][j][0] = a * costheta * sinphi;
			    mesh[i][j][1] = b * sintheta * sinphi;
			    mesh[i][j][2] = c * cosphi;

             
		    }



// Display ()    
for(int i=0; i < NVERTICES - 1; i++)
    {
        glBegin(GL_TRIANGLE_STRIP);
        for(int j=0; j < NVERTICES; j++)
        {
            glVertex3dv(mesh[i][j]);
            glVertex3dv(mesh[i + 1][j]);
        }
        glEnd();
    }