In an earlier post, I ended the story with the query, what is a krok?
There are numerous possibilities. The krok may be a coupon, note, or bill -- or possibly a unit used in coupons, notes, or bills. For example, I might print up a series of one-krok notes, five-krok notes, twenty-krok notes, 100-krok notes, million-krok notes, billion-krok notes, trillion-krok notes, or even quadrillion-krok notes.
So what use would that be? What would anyone want with a hundred kroks, or even a quadrillion kroks? By itself, nothing. But now, suppose I were the owner of a large estate demanding (and enforcing) rent, or a government demanding taxes, or simply a powerful criminal demanding tribute. I may demand payment in kroks. Since the payment is enforced, the payers need to get their hands on kroks somehow or other. This gives the kroks a certain value to them. For me, they're just coupons. I can print up as many as I choose. But others need them, so they might be willing to provide goods or services or money to me in exchange for kroks.
Compare with with Warren Mosler's account of a UMKC currency of community service.
There are other possibilities. For example, a krok may be a claim on an ounce of gold, or a pound of silver. This, of course, just transfers the question, "why the heck would you involve yourself with such a thing?" from kroks to the gold or silver. Except that people already view gold and silver as valuables.
I may invent an efficient way to produce liquid hydrogen for fuel, perhaps using nuclear fusion. Then a krok may be a kilogram of liquid hydrogen, or a claim on a kilogram of liquid hydrogen. Someone goes up to a hydrogen service station, presents five kroks, and fills his fuel take with five kilos of liquid hydrogen.
I may generate electricity. A krok then may be a claim on a kilowatt-hour of electrical energy.
One might create a krok currency identical to the Bitcoin. I have my doubts about bitcoins being accepted as a currency, at least until some large company or government demands payment in bitcoins.