Have you seen, one of the German soldier have a shield !!!
Yes, improvised trench armor, at least, I think it represents a piece improvised in the field, and not factory-produced, although there was also purpose-made armor developed and issued to troops.
The Germans had a piece of jointed frontal body armor that covered the chest and groin, too.
I understand, too, that as the trenches developed and both sides realized that they needed more protection that either the leather
Pickelhaube or cloth peaked service cap offered, they were influenced by medieval armor designs that were native to each country. The Germans'
Stahlhelm, for example, was supposed to have been influenced by the bassinet that was common in Germany in the 1400's or early 1500's. And the Brits' tin had was similar to the round pot helmet common in England in the late medieval period.
The WWI experts can probably add more info and correct me, if I'm wrong.
Prost!
Brad