**Stack of Blocks**

A dozen blocks are stacked on top of each other over the edge of the table seemingly defying gravity.

**What it shows:**

N objects of unit length can be stacked on top of each other so that the top object sticks out over the edge of the lecture bench by a distance equal to ^{1}

1/2 + 1/4 + 1/6 + 1/8 + ... + 1/(2N)

For N approaching ∞, the diverging infinite sum suggests that the top of the pile can stick out an infinite distance. In actuality the divergence is slow,^{ 2} and our more practical stack of a dozen 2 × 4 "blocks" can...