Your best card can drop a block instead of a coin. Walk up to it, pay to open it, and get a graphics card at or above the best level you own.

Only your single best card rolls for a block, and only from LVL 6 onwards. The rest of the rack does not take part, so a wall of potatoes will not find you anything.

Three kinds of block. Basic is common, Diamond is rarer and Quantum is rare. The rarer the block, the more it costs and the better its worst outcome: a Quantum block cannot give you anything below your best card.

Drop chances, rolled once per mining wave and a wave is six seconds: Basic 1.25%, Diamond 0.67%, Quantum 0.17%. In practice that is a Basic about every 8 minutes, a Diamond about every 15 minutes and a Quantum about once an hour.

What is inside, counted from your best card. Basic: one level below it 75%, the same level 20%, one above 5%. Diamond: the same level 60%, one above 30%, two above 10%. Quantum: one above 55%, two above 30%, three above 15%.

Opening a block plays a reveal on your screen: cards spin past, slow down, and the winner drops in with its name and level.

Blocks wait in your pit instead of replacing each other, so nothing is lost while you are away.

Every block takes room a coin could have used, and each extra block of the same kind takes more than the last. Sit on a hoard and your pit fills up, which stops the mining until you deal with them.

A block always drops when its roll comes up, even if there is no room left in the pit at all.

A block keeps the price and the cards it was found with. Growing your rack afterwards does not change what is already lying there, and a rebirth clears your blocks along with everything else.