They're the very first two publications for that "Modern dayý Pračlovek" collection (Modern day Caveman). The key concept was to represent caveman drawings in a very simple way and products which were applied at that time... and also in our days. The primary one — “Kuchyňa Pračloveka” (Caveman's Kitchen area) https://maplepublishers.com/blog/author/maplepublishers/page/3/