Weirs

Weirs keep a Confluence steady: without them a mid or great Confluence breaks into eddies. A weir calms one stream — the one it stands beside: set it within a block of the line between a side plinth and the center. The first weir on a stream calms 0.8 a second, the second half that, a third nothing. Set it by the stream with a rough thing — a turquoise thread will run to it.

A flume is a channel in the floor. Lay a line of flumes from a weir to a side plinth: if an eddy would knock that plinth's thing off, the weir holds it — once per Confluence. Light runs along connected flumes.

Float lanterns by a stream calm it too, and a lantern of its current's color twice as much. Next: "Rapids and Reach" and "Calm Stones".