Open tables anyone can walk into. Click a puzzle and you are in it — no account, nothing to install, and up to 10 people can work the same board at once. If somebody is already there, you will see their pieces move as they move them.
A room does not have to be started from scratch. Half-finished is often the nicest moment to arrive: the edge is usually done, the colours have been roughly sorted, and there is plenty left. Nothing is reserved and nobody is in charge — you pick up a piece and place it.
Then it is yours to start, and the next person to come along joins you. There are always tables open here, at every size from twelve pieces to five hundred, so there is never a wait for something to play. Rooms with somebody in them are shown first.
These rooms are open to anyone. To put specific people round a table instead, pick a picture and share the link the game gives you — solving one with friends works the same way, just without strangers. Browse the pictures to start one.