diff --git a/core/shared/src/main/scala/viz/vega/plots/Examples.scala b/core/shared/src/main/scala/viz/vega/plots/Examples.scala
index a6efb16..876f26e 100644
--- a/core/shared/src/main/scala/viz/vega/plots/Examples.scala
+++ b/core/shared/src/main/scala/viz/vega/plots/Examples.scala
@@ -523,32 +523,37 @@ case class Aninteractivescatterplotofglobalhealthstatisticsbycountryandyear_Lite
     using PlotTarget
 ) extends FromUrl(SpecUrl.Aninteractivescatterplotofglobalhealthstatisticsbycountryandyear_Lite)
 
-object BarChart 
-  extends viz.companions.AxisUtils:
+object BarChart extends viz.companions.AxisUtils:
+  import upickle.default.*
+  import ujson.Obj
+  import ujson.Value
 
-  trait BarData
+  trait BarData {}
 
   trait BarPlottable(val category: String, val amount: Double) extends BarData
   trait MarkColour(val colour: String) extends BarData
 
-  val takeColourFromData : (ujson.Value => Unit) = spec => spec("marks")(0)("encode")("update")("fill") = ujson.Obj("field" -> "colour")
+  val takeColourFromData: (ujson.Value => Unit) = spec =>
+    spec("marks")(0)("encode")("update")("fill") = Obj("field" -> "colour")
+
+  //def replaceBarData[T <: BarData](d: Seq[BarData]) = writeJs(d)
 
   given enc[JsValue, T <: BarData](using upickleDefault: ReadWriter[T]): ReadWriter[T & BarData] =
     readwriter[ujson.Value].bimap[T & BarData](
       in =>
-        var toMerge: scala.collection.mutable.ArraySeq[ujson.Obj] = scala.collection.mutable.ArraySeq()
-        val vanilla = upickle.default.writeJs(in)(upickleDefault).obj
+        var toMerge: scala.collection.mutable.ArraySeq[Obj] = scala.collection.mutable.ArraySeq()
+        val vanilla = writeJs(in)(upickleDefault).obj
 
         in match
-          case colorful: MarkColor =>
-            toMerge :+= ujson.Obj("colour" -> colorful.color)
+          case colorful: MarkColour =>
+            toMerge :+= Obj("colour" -> colorful.colour)
           case _ => ()
 
         in match
-          case xyData: XYPlottable =>
-            toMerge :+= ujson.Obj("category" -> xyData.x, "amount" -> xyData.y)
+          case barData: BarPlottable =>
+            toMerge :+= Obj("category" -> barData.category, "amount" -> barData.amount)
           case _ => ()
-        toMerge.fold[ujson.Obj](vanilla) { case (start, next) => start.value ++ next.value },
+        toMerge.fold[Obj](vanilla) { case (start, next) => start.value ++ next.value },
       in => ??? //upickle.default.read[T & BarData](in)
     )