經典案例：數(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)(shù)字沙盤(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)(pán)