It does not work. It works as well as it ever will. If you have more

then 80 points in your data set, only the first 80 will be
printed. There is no x-axis. There is just a list of points. Scaling
does not help.
I did, however, get it to work in black and white.

go.mod

@@ -4,5 +4,6 @@ go 1.16
 
 require (
 	github.com/gizak/termui/v3 v3.1.0
+	github.com/nsf/termbox-go v0.0.0-20190121233118-02980233997d
 	gonum.org/v1/plot v0.9.0
 )

screenplot.go

@@ -3,54 +3,87 @@
 package main
 
 import (
-	"fmt"
 	"math"
+
 	ui "github.com/gizak/termui/v3"
 	"github.com/gizak/termui/v3/widgets"
+	tb "github.com/nsf/termbox-go"
+)
+
+// render overrides the library function. It was not respecting
+// background color, so I trashed it.
+func render(items ...ui.Drawable) {
+	for _, item := range items {
+		buf := ui.NewBuffer(item.GetRect())
+		item.Lock()
+		item.Draw(buf)
+		item.Unlock()
+		for point, cell := range buf.CellMap {
+			if point.In(buf.Rectangle) {
+				tb.SetCell(
+					point.X, point.Y,
+					cell.Rune,
+					tb.Attribute(tb.ColorWhite), tb.ColorBlack,
 				)
+			}
+		}
+	}
+	tb.Flush()
+}
 
-func breaker(x interface{}) {}
-func copyToData (y []float32) ([][]float64){
+// copyToData puts the data in a slice of slices with crazy
+// unnecessary double precision.
+func copyToData(y []float32) [][]float64 {
 	data := make([]float64, len(y))
 	for i := range y {
 		data[i] = float64(y[i])
 	}
-	data[0] = data[1]
 	return [][]float64{data}
 }
 
+// wipeFirst Takes the first n entries and sets them to the n+1'th
+// so we effectively discard the first entries where the estimates are
+// so bad. We do not have to return anything, since the slice is a
+// reference structure anyway.
+func wipeFirst(x []float64, n int) {
+	for i := 0; i < n; i++ {
+		x[i] = x[n]
+	}
+}
 
+// scrnPlot puts the data in a retro-look plot.
 func scrnPlt(pi, stdErr []float32) error {
-	fmt.Println()
+	const toWipe = 12
 	marker := widgets.MarkerDot
 	dotMarkerRune := '.'
 
-
 	p1 := widgets.NewPlot()
 	p1.Title = " π "
 	p1.Data = copyToData(pi)
+	wipeFirst(p1.Data[0], toWipe)
 	p1.Marker = marker
 	p1.DotMarkerRune = dotMarkerRune
-	p1.PlotType = widgets.ScatterPlot
-	p1.Border = true
 
 	p2 := widgets.NewPlot()
+	p2.PlotType = widgets.ScatterPlot
 	p2.Title = "standard error"
 	p2.Data = copyToData(stdErr)
 	p2.DotMarkerRune = dotMarkerRune
 	p2.Marker = marker
+	wipeFirst(p2.Data[0], toWipe)
 
 	p3 := widgets.NewPlot()
 	p3.Title = "abs error"
 	{
 		d := make([]float64, len(pi))
 		for i, piV := range pi {
-			d[i] = math.Pi - float64(piV)
+			d[i] = math.Abs(math.Pi - float64(piV))
 		}
 		p3.Data = [][]float64{d}
+		wipeFirst(p3.Data[0], toWipe)
 	}
-
-
+	p3.DotMarkerRune = dotMarkerRune
+	p3.Marker = marker
 
 	if err := ui.Init(); err != nil {
 		return err
@@ -69,14 +102,3 @@ func scrnPlt(pi, stdErr []float32) error {
 	}
 	return nil
 }
-
-// This was how I wanted to do it, but the library does
-// not seem to respect background colours.
-//	ui.Theme = thm
-// nrmlStyle := ui.NewStyle (ui.ColorWhite, ui.ColorBlack)
-// thm := ui.Theme
-// thm.Block.Title = nrmlStyle
-// thm.Plot.Axes = ui.ColorWhite
-// thm.Plot.Lines = []ui.Color{ui.ColorWhite}
-// thm.Default = ui.NewStyle(ui.ColorWhite, ui.ColorBlack)
-// thm.Block.Border = nrmlStyle