Convert from a blocked_representation to its inner_representation by selecting a block based on its position, taking a slice of the input pattern. In counting the position, zero/empty blocks are ignored, and counting can be from the left or right end.
some_sbc get_position
Print the currently set position for the block to be extracted.
some_sbc set_position block_number
Indicate the direction and distance of travel in finding a zero block when
applying some_sbc. For block_number, 0 is the first non-zero block from
the left, 1 the second, and so on. -1 is the first non-zero block from the
right, -2 the second, and so on.