> where is the 'tail' in light of what's given? is it in the 'car' or
> 'cdr'? the ASCII art in http://www.software-lab.de/doc/ref.html#cell
> is a bit vague.
A better place is "doc/ref.html#symbol". Scrolling down a little, there
is an ASCII art of a property list.
So the tail of a symbol is actually the CAR part of that cell (the
symbol's value is in the CDR part (denoted as VAL in the diagrams)).
In both cases, the CAR in case of a cell, and the VAL in case of a cell
are directly pointed to by the tagged pointer, so accessing the CAR or
VAL is a single pointer-dereference.