Chipmixer rolling deep in the thread again I see
there is an anology about glass safety deposit boxes that kinda works, but more explains the semi anon nature of bitcoin than the blockchain, which to me is the whole of this. Charlie Shrem, the dude that used to run that service I talked about a few posts ago, had this explanation of bitcoin right before he went to prison (he is out now). Basically, he got accused of what the btce admin guy was accused of (facilitating large scale money laundering, and he just got out of jail kinda recently). Anywho, try this:
https://motherboard.vice.com/en_us/article/4x3pdw/bitcoin-for-prisonThe answer is yes. All you really need for a Bitcoin-like currency to work is the ability to keep track of transactions in a central ledger, which is double-checked frequently by users.
Without a computer or cell phone, prisoners would need to run a ledger completely offline from behind the prison walls. In other words, we'd need a physical notebook to keep track of all the transactions. Instead of swapping physical cans of mackerel, we'd simply write down the amounts in the notebook.
Let's call our prison-version of Bitcoin Mackerelcoin, or MAK.
Say I'm working out in the gym, and Dave needs to pay John 25 MAK for his monthly workout training. Instead of having to fill his pockets with 25 tins of fish, he'd simply ask me to move the funds from his account to John's. I'd open the ledger and write down "Dave paid John 25 MAK," and the date. Then I'd subtract 25 MAK from Dave's balance and add 25 MAK to John's.
(This isn't quite the same as Bitcoin, because as the single node, I'm acting similar to a banker. If we really wanted to imitate Bitcoin perfectly, many inmates throughout the prison would be keeping track of these transactions and then synchronizing them together, just like nodes in the Bitcoin network. When Dave paid John 25 MAK for a workout, every inmate in the yard would take out their notebook and jot down the transaction. Later, when John pays Tim 2 MAK for a haircut, all the other inmates in the salon would take out their notebooks and each record the transaction. Then at the end of the day, all the inmates would meet together and enter all the transactions into the main ledger. It's sort of like the Island of Yap, where the residents used enormous stone coins that were too heavy to move—when money changed hands, everyone in the village simply spread the word of its new owner.)
So remember, bitcoin is cans of mackerel in a prison yard with a notebook. Clear as water.