<span metal:define-macro="OUTER">
  AAA
  <span metal:define-macro="INNER">INNER</span>
  BBB
</span>

<xxx metal:use-macro="OUTER">
</xxx>

<xxx metal:use-macro="INNER">
</xxx>

<span metal:define-macro="OUTER2">
  AAA
  <xxx metal:define-slot="OUTERSLOT">
  <span metal:define-macro="INNER2">INNER</span>
  </xxx>
  BBB
</span>

<xxx metal:use-macro="OUTER2">
</xxx>

<xxx metal:use-macro="INNER2">
</xxx>

<xxx metal:use-macro="OUTER2">
  <yyy metal:fill-slot="OUTERSLOT">OUTERSLOT</yyy>
</xxx>

<span metal:define-macro="OUTER3">
  AAA
  <xxx metal:define-slot="OUTERSLOT">
  <span metal:define-macro="INNER3">INNER
    <xxx metal:define-slot="INNERSLOT">INNERSLOT</xxx>
  </span>
  </xxx>
  BBB
</span>

<xxx metal:use-macro="OUTER3">
</xxx>

<xxx metal:use-macro="OUTER3">
  <yyy metal:fill-slot="OUTERSLOT">OUTERSLOT</yyy>
</xxx>

<xxx metal:use-macro="INNER3">
</xxx>

<xxx metal:use-macro="INNER3">
  <yyy metal:fill-slot="INNERSLOT">INNERSLOT</yyy>
</xxx>

<xxx metal:use-macro="INNER3">
  <yyy metal:fill-slot="INNERSLOT">
    <zzz metal:define-macro="INSLOT">INSLOT</zzz>
  </yyy>
</xxx>

<xxx metal:use-macro="INSLOT"></xxx>