Each subblock has a maximum length of 255 bytes and is preceded by one byte indicating the number of bytes of data in the subblock. The series of subblocks is completed by an empty subblock (a single 0-byte indicating a subblock with 0 bytes of data). For the sake of clarity, the above table is presented as constructed from chains of increasing length. This scheme may work, but the table consumes an unpredictable amount of memory. Memory can be stored in practice by noting that each new string to be recorded consists of a previously stored string that is extended by one character. It is economical to store only two words at each address: an existing address and a character. Built-in Adobe Flash objects and MPEG are used on some websites to display simple videos, but require the use of an additional browser plug-in.