One of the scenarios from the "Rebels and Patriots" rules requires two engineer units of 6 figures each. So I have one unit which is the process of preparing a river crossing while defending from enemy forces, and the other crossing the river to work on the other side of the waterway.
The clothed figures I believe are Black Hussar (nee Westphalian Miniatures). The bare-chested lads are plastic ex-Warlord Celt torsos added to by the author. A different headdress would change them to any era or army you wish.