Remark: these are special cases of the schema "all strings that contain exactly one instance of pattern X in possible positions Y", where in the first case X is "0" and Y is "anywhere" and in the second X is "00000000" and Y is "any position that's a multiple of 8 bits".

(Of course there are plenty of other prefix-free sets of bitstrings. For instance: interpret blocks of 8 bits as characters as in Kindly's second example, and say that a valid program is anything that begins with a "(", has properly matched parentheses, and ends with the ")" matching the first "(". This doesn't have the convenient property that every bitstring begins with a valid program; for examples that do, take the exponential Golomb coding or the Elias omega coding of natural numbers.