The horizontal and vertical pieces of each grid block can be placed inside each other, which provides great stability for construction play. Houses, Castles or other structures can be built with these amazingly shaped blocks. In addition, other Bauspiel products, like the Acrylic cubes can be added as windows in each block. The undyed lattice blocks are made of solid Alder wood and measure 17.5 x 17.5 x 2.5cmH. please note you will get one grid, but can purchase multiple