A page of infinite sums
This is not only a page of dynamic HTML layout exercise,
but also an illustration of how some infinite sums converge to finite values.
The layout doesn't look so good in IE, sorry.
i've since worked out that sum[i: 0->infinity, 1/(d^i)] is d/(d-1).
it took a little bit of math to get there, so it surprised me that it's such a simple formula.