void
spiral(Client *c, float fact, XRectangle *r, XRectangle *rp) {
	if(fact == 0) {
		rp->width = rp->height = 0;
		return;
	}

	static int pos = 1;
	float f = fact == 1 ? 1 : 0.5;

	switch(pos) {
		case 0:  /* left */
			tileh(c, f, r, rp);
			pos = 1;
			break;
		case 1:  /* top */
			tilev(c, f, r, rp);
			pos = 2;
			break;
		case 2:  /* right */
			tileh(c, f, &((XRectangle){ r->x + r->width * (1 - f), r->y, r->width, r->height }), rp);
			r->width  -= rp->width;
			pos = 3;
			break;
		case 3:  /* bottom */
			tilev(c, f, &((XRectangle){ r->x, r->y + r->height * (1 - f), r->width, r->height }), rp);
			r->height -= rp->height;
			pos = 0;
			break;
	}

	if(fact == 1)
		pos = 1;  /* reset to initial value */
}