Paraboloid

void paraboloid(int slices,int subdivisions,int height)
{
    int h,i;
    float alpha;
    float fh;
    float dh=(float)height/(float)subdivisions;
    float dx=PI2/slices;
    glBegin(GL_TRIANGLE_STRIP);
    for(h=0,fh=0.0f;h<subdivisions;h++,fh+=dh)
    {
        for(i=0,alpha=0.0f;i<=slices;i++,alpha+=dx)
        {
            glVertex3f(fh*cosf(alpha),fh*fh,fh*sinf(alpha));
            glVertex3f((fh+dh)*cosf(alpha),(fh+dh)*(fh+dh),fh*sinf(alpha));
        }
    }
    glEnd();
}