This is my Lego version of a German Panzer IV tank from World War II. This particular model is the Ausf. H, which was the main production version. It was the most produced tank of Germany.
The weird walls on the tank’s sides and turret are called Schurzen skirts, and they helped with protecting the hull. They were pretty effective against HEAT rounds, forcing the round to prematurely detonate. The jet produced by the detonation lost effectiveness with distance and would dissipate in the space between the Schurzen and tank hull.
Since so many vehicle variants are housed on the Panzer IV chassis, I made the turret and rear exhaust removable, which different modules can then replace. One of the pictures below shows this feature.