Many will be disinclined to use their brains to work it out, but those
who do will remember it, and that after all is the merit of an
advertisement. A puzzle which may be patented and sold to the advertiser
promises much greater profit. See the “Chinese-Get-Off-the-Earth
Puzzle.” A puzzle of this kind is commonly sold exclusively to one firm,
and ought to bring quite a sum of money to the inventor.