A ladder is a vertical or inclined set of rungs or steps.
Use as a trestle
A short ladder can be used for a spanking in the bent-over-object position, like a trestle or barstool, as shown in the cartoon by Dave Ell. Padding on top of the ladder is recomendable for a more comfortable position.
A step ladder with a platform to lie over can be used like a spanking bench.
The Swedish Ladder, also known as wall bars, is a ladder-like gymnastics apparatus mounted on a wall. It was invented in the early 1800s by Per Henrik Ling (1776-1839) and improved by his son Hjalma Ling (1820-1886).
Use for bondage/whipping