Common Lisp the Language, 2nd Edition
A bit-vector can be written as the sequence of bits contained in the string, preceded by #*; any delimiter character, such as whitespace, will terminate the bit-vector syntax. For example:
#*10110 ;A five-bit bit-vector; bit 0 is a 1 #* ;An empty bit-vector
The bits notated following the #*, taken from left to right, occupy locations within the bit-vector with increasing indices. The leftmost notated bit is bit-vector element number 0, the next one is element number 1, and so on.
The function prin1 will print any bit-vector (not just a simple one) using this syntax, but the function read will always construct a simple bit-vector when it reads this syntax.