There are 12 polygon pieces include in brain master. Each of these pieces covers 5 spaces on the board and is calles a 5-space block. In brain master the term slab refers to a group of 5-space block which completely covers the space defined by the slider on the game board. For example, a SLAB 4 indicates a challenge for which the slider is placed between number 4 and 5 of the game board: 4 5-space block must be arranged together to cover the four lines of the game board. Brain master includes 500+ Challenges for you.