A confluence is a meeting, joining, gathering at one point. In geography, a confluence is where two streams or rivers meet, like the confluence of the Missouri and the mighty Mississippi rivers near St. Louis.
Here two patterns are joined: Lazy River and Stream.
The patterns use the same stitch, but Lazy River is worked with the yarn held double on large needles, while Stream is worked with small needles, and a single strand of yarn.
Charted and written.