https://i.nostr.build/aKxv9o9XHmacDY0w.png
It’s the year 2040 and Bobby walks into a coffee shop, slaps down a freshly printed Federal Reserve Note, and says, 'One black coffee, please.'

The barista, a kind-eyed woman with a BIP-398 compliant Lightning node glowing softly under her apron, squints at the unfamiliar green paper. 'Sorry, hon,' she says, not unkindly. 'We don't take… collectibles. We take real money.' She gestures to the sign behind her:
₿ ITCOIN | SATS | GOLD GRAINS | SILVER OUNCES | PHYSICAL LABOR (15min min.)

Flustered, Bobby points to the note. 'But it says right here—Twenty Dollars!'

'Oh, sweetie,' she chuckles, handing it back. 'My grandma told me about those. You can probably trade it to a nostalgia streamer for a few sats. But for coffee?' She leans in and whispers, 'You need real energy.'

Just then, a miner in the corner—who’s been powering the shop’s mesh node by pedaling a bicycle generator—chimes in between breaths: 'He can… pump… my bike… for five… minutes… for an espresso.'

Bobby looked at the bike. He looked at the note. He looked at the espresso.

He started pumping.