Polkadot

 Polkadot is a digital contract protocol. It has tokens that assign governance authority to holders, trusted miners in essence. The effect is meant to incur stable contact completion, which they call parachains. So, in essence, a simple version between my smart card and the corner grocery would be the expansion and contraction of accounts, co validated by either card. My card might toss a chunk of cash, with my permission at the proper time, otherwise I am covered for stop and go shopping. So I don't have the hassle of accumulating the ledger, and checking my cash account; that is done properly, separately within our smart cards. The contract will have a bounds, but otherwise will make ad hoc choices of when to rebalance according to my local account congestion. They have timeouts, seems fairly sandbox compatible. We can see the payoff, each of these contract management mechanisms want a spot on the new smart card, that leads them into a huge range of possible applications into the handheld.

The winner will be like the 'c' language of contracts. It will be made of the tiny components of spectre compatible contract actions in the cache.  Then it chains cache actions together in ad hoc expansions and contraction networks. But it always tends to clear the contract, fall to the last stable exit.

The spectre complete contract is a spanning tree between trusted miners doing ledger swaps, at its basic.  But it has a complement, a structured network of trading pits.  One is over the counter, the other is auction. This is a good starting point for contract management, but it introduces a role for bearer cash as the trading pits need spectre compatible hot wallet. Sandbox is a mix of over the counter and trading pits and static ledgers as needed. They are properly segmented by the canonical monetary system methods. And these methods are partly enforced in spectre compatible kernel methods set at the foundry.

Yes to Polkadot, definitely worth a try.