> That sounds great.  You could make something up, or we could all look
> for the worst example we find while working on our examples from
> existing SRFIs.

This definition of 'arg-ands' from SRFI 51 is pretty gnarly:

   <code class="syntax def">(<span>arg-ands</span>
     [common &lt;<var class="opt">caller</var>&gt;]
     ([&lt;<var class="opt">caller</var>&gt;]
     &lt;<var class="opt">variable</var>&gt;
     &lt;<var class="opt">expr</var>&gt;
     <var class="rest">...</var>)
     <var class="rest">...</var>)</code>
   (syntax)

Then again, it's pretty twisty without the <var>s too.