Also, the highly functional spikes one often finds on top of the merlons of a crenellated wall. These don't only look badass, but could serve as anchors for temporary wooden superstructures, or hoardings, during siege. Also, one could stick a long spear between two of them without anyone being able to swing back with a sword because they would get in the way. However, the merlons are often too high for this maneuver.