Answer of pic in go tour

pic.go

package main

import "golang.org/x/tour/pic"

func Pic(dx, dy int) [][]uint8 {
	z := make([][]uint8, dy)
	for i := range z {
		z[i] = make([]uint8, dx)
		for j := range z[i] {
			z[i][j] = uint8(i*j)
		}
	}
	return z
}

func main() {
	pic.Show(Pic)
}