1.
如图,在\(Rt\triangle \)\(ABC\)中,\(\triangle \)\(ABC\)面积为\(1\),\(∠\)\(ACB\)\(= 90^{\circ}\),点\(D\)、点\(E\)、点\(F\)分别是\(AC\),\(AB\),\(BC\)边的中点,连接\(DE\)、\(EF\),得到四边形\(EDCF\),它的面积记作\(S\);点\(D\)\({\,\!}_{1}\)、点\(E\)\({\,\!}_{1}\)、点\(F\)\({\,\!}_{1}\)分别是\(EF\),\(EB\),\(FB\)边的中点,连接\(D\)\({\,\!}_{1}\)\(E\)\({\,\!}_{1}\)、\(E\)\({\,\!}_{1}\)\(F\)\({\,\!}_{1}\),得到四边形\(E\)\({\,\!}_{1}\)\(D\)\({\,\!}_{1}\)\(F F\)\({\,\!}_{1}\),它的面积记作\(S\)\({\,\!}_{1}\),照此规律作下去,则\(Sn\)\(=\) .