@Q:
RETURN FLATTEN( [ <span class="hljs-number">1</span>, <span class="hljs-number">2</span>, [ <span class="hljs-number">3</span>, <span class="hljs-number">4</span> ], <span class="hljs-number">5</span>, [ <span class="hljs-number">6</span>, <span class="hljs-number">7</span> ], [ <span class="hljs-number">8</span>, [ <span class="hljs-number">9</span>, <span class="hljs-number">10</span> ] ] ], <span class="hljs-number">2</span> )

@R
[
  [
    <span class="hljs-number">1</span>,
    <span class="hljs-number">2</span>,
    <span class="hljs-number">3</span>,
    <span class="hljs-number">4</span>,
    <span class="hljs-number">5</span>,
    <span class="hljs-number">6</span>,
    <span class="hljs-number">7</span>,
    <span class="hljs-number">8</span>,
    <span class="hljs-number">9</span>,
    <span class="hljs-number">10</span>
  ]
]