title: Tour of Go exercise #18: Slices
body: <p>I am trying to complete the <a href="https://tour.golang.org/moretypes/18" rel="noreferrer"><code>Exercise: Slices</code> from the Go Tour</a>.<br>
  However I don't really understand what I'm being asked to do.</p>
  
  <blockquote>
    <p>Implement Pic. It should return a slice of length dy, each element of which is a slice of dx 8-bit unsigned integers. When you run the program, it will display your picture, interpreting the integers as grayscale (well, bluescale) values.</p>
  </blockquote>
  
  <p>I have the following code</p>
  
  <pre><code>package main
  
  import "golang.org/x/tour/pic"
  
  func Pic(dx, dy int) [][]uint8 {
      a := make([][]uint8, dy)
      return a
  }
  
  func main() {
      pic.Show(Pic)
  }
  </code></pre>
  
  <p>I have created the slice of length dy so far. However I don't understand the next step. Do I need to create a for loop in which I assign every element of my slice to a value in the range of dx?  I don't ask for code but rather for an explanation/clarification</p>