Men Ascending Vertical Ladders yet Moving Apart

Problem

$2$ men each ascend a vertical ladder, at the same speed, and yet they get further apart.

Explain.

Solution 1

The men are at the center of the Earth, ascending in opposite directions.

$\blacksquare$

Solution 2

To a first approximation, Earth is a sphere.

So, anywhere you place $2$ vertical ladders, their upper ends will be further apart from their lower ends.

Hence the ladders may be anywhere on the surface of the Earth.

$\blacksquare$

Historical Note

This puzzle is typical of those found in collections of Victorian amusements.

Sources

• 1992: David Wells: Curious and Interesting Puzzles ... (previous) ... (next): Henry van Etten: $118$