     mainline.push PS.new_random_async_value_source "just a few words".split /\s/
     mainline.push PS.$watch ( d ) -> whisper 'mainstream', jr d
     mainline.push PS.$wye PS.pull byline...
+    mainline.push PS.$show title: 'confluence'
+    mainline.push PS.$collect()
+    mainline.push PS.$show title: 'mainstream'
+    mainline.push PS.$drain -> help 'ok'; resolve()
+    PS.pull mainline...
+    #.......................................................................................................
+    return null
+  await demo()
+  return null
+
+#-----------------------------------------------------------------------------------------------------------
+wye_3b = ->
+  #.........................................................................................................
+  demo = -> new Promise ( resolve ) ->
+    bysource  = PS.new_push_source()
+    byline    = []
+    byline.push bysource
+    byline.push $ ( d, send ) ->
+      if CND.isa_text d
+        send d.length
+      else
+        send d
+      return null
+    byline.push PS.$watch ( d ) -> whisper 'bystream', jr d
+    #.......................................................................................................
+    mainline = []
+    mainline.push PS.new_random_async_value_source "just a few words".split /\s/
+    mainline.push PS.$watch ( d ) -> whisper 'mainstream', jr d
+    mainline.push PS.$wye PS.pull byline...
+    mainline.push $ ( d, send ) ->
+      if CND.isa_text d
+        bysource.send d
+        send d
+      else
+        send d
+      return null
     mainline.push PS.$show title: 'confluence'
     mainline.push PS.$collect()
     mainline.push PS.$show title: 'mainstream'

  return null

#-----------------------------------------------------------------------------------------------------------
wye_3 = ->
  #.........................................................................................................
  demo = -> new Promise ( resolve ) ->
    byline    = []

  # pull_pair_2()
  # wye_1()
  # wye_2()
  wye_3b()
  # wye_4()
  # duplex_stream_3()





