In Unicode, a block is defined as one contiguous range of code points. Blocks are named uniquely and have no overlap. They have a starting code point of the form nnn0 and an ending code point of the form nnnF. A block explicitly can include code points that are unassigned and non-characters. Code points not belonging to any of the named blocks, e.g. in the unassigned planes 3–13, have the value block="No_block".