It is well know that quadratic integers are either 
where 
(first kind) and 
is square free, or 
where 
are both odd and 
(second kind).
It is also well known that the confrac expansion of a quadratic surd
is (ultimately) periodic. If we plot the period of 
versus
the period of 
for all 
in 
, we obtain FIG. 1.1,
i.e. "quite equal or quite triple".
