title: updating one position in a slice of slices results in multiple updates
body: <p>I learning go and playing with slices but I have a problem</p>
  <p>I have a default matrix with &quot;.&quot;, but when I try to change the position 0,0 to a &quot;#&quot; symbol all the n,0 position have a  &quot;#&quot;, in other words, I start with this:</p>
  <pre><code>[. . . . .]
  [. . . . .]
  [. . . . .]
  [. . . . .]
  [. . . . .]
  </code></pre>
  <p>Modify the 0,0 position with this function:</p>
  <pre><code>func drawSym(table *[][]string) {
      (*table)[0][0] = &quot;#&quot; 
  }
  </code></pre>
  <p>And i get</p>
  <pre><code>[# . . . .]
  [# . . . .]
  [# . . . .]
  [# . . . .]
  [# . . . .]
  </code></pre>
  <p>When i want a matrix like this</p>
  <pre><code>[# . . . .]
  [. . . . .]
  [. . . . .]
  [. . . . .]
  [. . . . .]
  </code></pre>
  <p>The full code of the program is in playground <a href="https://play.golang.org/p/xvkRhmNvdIP" rel="nofollow noreferrer">https://play.golang.org/p/xvkRhmNvdIP</a></p>