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Spatial rummy, 2 to 4 players

Everyone builds one shared 4 by 4 grid. Sixteen squares, and nobody can take them apart. When the grid fills, whoever is holding the least wins.

What you play with

• One standard deck plus 4 jokers, 56 cards
• A 4 by 4 grid, a draw pile and a face-up discard
• A hand of 7 cards

Rows

Every row has to be able to end up as one of two things.

Run

Four consecutive cards of one suit. Ace is low, so A-2-3-4 is the lowest and 10-J-Q-K is the highest. No wrapping around.

Set

Four cards of one rank, one of each suit.

Where you put a card inside its row makes no difference to whether it is legal. The app arranges rows tidily for reading, runs ascending and sets in suit order, but the rule does not care.

Placing a card

You can put a card in an empty square only if that row can still finish.

• The first card in a row can be anything
• The second real card decides the row. Same rank makes it a set, same suit makes it a run, anything else is illegal
• Once a row has a type, everything after has to agree with it

Jokers

• One joker per row, at most
• A joker is never declared. It stands for whatever single card the row needs, and that can change as the row changes
• A row with a joker is legal as long as there is some card the joker could be that lets the row finish
• One joker covers one gap. It cannot fill two

A joker on its own does not decide anything. A row holding a joker and one real card is still undecided between a run and a set until a second real card settles it.

Your turn

Play one card from your hand, or do an upgrade, or do a shift.

If none of those three is possible, then and only then you take the top discard, if it can go straight down, or you draw. A drawn card you can play goes down at once. A drawn card you cannot play joins your hand and you discard back to seven.

If you have to draw and the pile is empty, the game is over.

Finishing a row

Complete a row and you get one extra turn straight away. Complete another on that extra turn and you get nothing more. Bonus turns never chain.

If the placement that completes a row also fills the last square on the grid, the game ends there and the bonus turn is never played.

Upgrade

Swap a joker out of a completed row for a real card from your hand that keeps the row valid. That is your whole turn.

• The row has to be full. A joker in a half-built row cannot be upgraded
• The freed joker has to go somewhere immediately, either into another legal empty square or into your hand
• One joker per row still applies wherever it lands
• You only get a bonus turn if the joker's new position completes a row

Often more than one card would do. A row of 6♠ 7♠ 8♠ and a joker will take either the 5♠ or the 9♠. The rule only asks whether your card keeps the row valid, not which card the row was "really" waiting for.

Shift

Instead of playing into an empty square, play a card into a completed run and push one card off the end. Sets never shift.

The row has to still be a valid run once exactly one card has come out. Whatever is pushed off goes face up on the discard, joker or not.

The card you played stays in the row, and the card that leaves has to be one of the four that were already there. You cannot push out the card you just played, which would leave the row untouched and turn shift into a free discard.

Ending and scoring

The game ends the moment the grid fills, or when someone has to draw and the pile is empty.

Count what is left in your hand. Lowest total wins.

Ties go to whoever holds fewest cards. Still tied, the win is shared.

How it differs from the other two