Broken...but why?

main.go

package main

import (
	"fmt"
	"private/point/point"
)

func main() {

	//tag::NewPoint[]
	p := *new(point.Point)
	p.X = 1
	p.Y = 2
	//end::NewPoint[]

	//tag::PointLiteral[]
	p = point.Point{1, 2}
	//end::PointLiteral[]

	//tag::TranslatingPoints[]
	q := p.Translate(5, 5)
	fmt.Printf("Translated %v to %v\n", p, q)
	//end::TranslatingPoints[]

	//tag::TranslatingPointers[]
	qP := &point.Point{1, 2}
	qP.TranslatePointer(5, 5)
	fmt.Printf("Translated using pointer to %v\n", qP)
	//end::TranslatingPointers[]

	//tag::PrintingPointAndColorPoint[]
	r := point.ColorPoint{point.Point{1, 4}, point.BLUE}

	fmt.Printf("Point: %v\n", p)
	fmt.Printf("Color Point: %v\n", r)
	//end::PrintingPointAndColorPoint[]

	//tag::CalculatingDistance[]
	fmt.Printf("Dist b/w p and q = %v\n", p.DistanceTo(r))
	fmt.Printf("Dist b/w q and p = %v\n", r.DistanceTo(p))
	//end::CalculatingDistance[]
}

point.go

package point

import "math"

//tag::PointStruct[]
type Point struct {
	X, Y float64
}

//end::PointStruct[]

//tag::ColorPoint[]
const (
	BLUE  = iota
	RED   = iota
	GREEN = iota
)

type ColorPoint struct {
	Point Point
	Color int
}

//end::ColorPoint[]

//tag::Translate[]
func (p Point) Translate(xDist float64, yDist float64) Point {
	return Point{p.X + xDist, p.Y + yDist}
}

//end::Translate[]

//tag::TranslatePointer[]
func (p *Point) TranslatePointer(xDist float64, yDist float64) {
	p.X = p.X + xDist
	p.Y = p.Y + yDist
}

//end::TranslatePointer[]

//tag::DistanceCalculator[]
type DistanceCalculator interface {
	Coordinates() Point
	DistanceTo(d DistanceCalculator) float64
}

//end::DistanceCalculator[]

//tag::PointSatisfiesDC[]
func (p Point) Coordinates() Point {
	return p
}

func (p Point) DistanceTo(d DistanceCalculator) float64 {
	q := d.Coordinates()
	sqOfXDist := math.Pow(p.X-q.X, 2)
	sqOfYDist := math.Pow(p.Y-q.Y, 2)
	return math.Sqrt(sqOfXDist + sqOfYDist)
}

//end::PointSatisfiesDC[]

//tag::ColorPointSatisfiesDC[]
func (cp ColorPoint) Coordinates() Point {
	return cp.Point
}

func (cp ColorPoint) DistanceTo(d DistanceCalculator) float64 {
	p := cp.Point
	q := d.Coordinates()
	sqOfXDist := math.Pow(p.X-q.X, 2)
	sqOfYDist := math.Pow(p.Y-q.Y, 2)
	return math.Sqrt(sqOfXDist + sqOfYDist)
}

//end::ColorPointSatisfiesDC[]