Amusing
Attach book (B) to door (D) of cage (C) containing trained attack rabbit (R) by string (S)... when a potential infringer (i.e. our customer) (I) attempts to copy book (B) without use of authorized carrot (AC) to pacify rabbit (R) or cutting the string (S) with authorized scissors (AS), rabbit (R) will be released.(slightly edited version of John Zulauf's Rube Goldberg TPM)
