The drawing is based on the early French Children's Signs — though Croatia is also a strong possibility. The shape and the background colour comes from the New World (e.g. Argentina).

The girl's headgear looks like a hard hat and the boy's probably wearing a soldier's cap. A clever piece of propaganda for the army: We care, it says. The boy's keeping the girl from inadvertently stepping into a mine field. The helmet gives her some protection against flying body parts of people less cared for.

One question remains: What's the weird thing at his elbow?