用4种不同形态的L型骨牌覆盖一个给定的特殊棋盘上除特殊方格以外的所有方格，且任何2个L型骨牌不得重又能叠覆盖。-In four different forms of L-type domino covering a given special special squares on the board in addition to all other boxes, and any two L-shaped dominoes can not be re-stacked coverage.