War machine on Trajan\'s Column

[Epictetus]

You have to remember that the poor saps back in Rome sculpting it may have had no idea what it is they are supposed to be depicting, hence it looks like the bastard child of a washing machine and an autogyro.

You know, I have no experience or knowledge of ancient roman siege machinery whatsoever. If someone plopped down a copy of Vitruvius in front of me:

He explained the principles of the borer as follows: that the machine itself resembled the tortoise, but that in the middle it had a pipe lying between upright walls, like the pipe usually found in catapults and ballistae, fifty cubits in length and one cubit in height, in which a windlass was set transversely. On the right and left, at the end of the pipe, were two blocks, by means of which the iron-pointed beam, which lay in the pipe, was moved. There were numerous rollers enclosed in the pipe itself under the beam, which made its movements quicker and stronger. Numerous arches were erected along the pipe above the beam which was in it, to hold up the rawhide in which this machine was enveloped.

On Architecture, 13.7

...and told me to make a drawing of it, I would probably draw something similar to what is on the Column. Trying to put in windlasses (those barrels?), numerous rollers, a pipe, blocks... yeah, I would probably draw something like that. Maybe it was a confused sculptor trying to make a borer based upon a description only.