To prevent the mill from blowing over it is anchored to the concrete foundations. In my model i'm not using any concrete and this windmill probably wasn't build with a concrete foundation. So i made the anchors using big stones as was common to do for small mills like these.
The raw materials
Drilling holes in stones cost me 3 drills for 4 holes
Hooks glued in place with epoxy
adding the anchors to the "achtkant stijl"
The wind anchors in place