Anchor Stones are small stone architectural building blocks made from quartz sand, chalk, and linseed oil. They are sold sequentially in sets with an instruction booklet of plans for various constructions. This is a repository of additional constructions that can be made.
Putting Anchor Stones into their storage box can be a puzzle. Thankfully, all sets come with a packing plan on the inside lid of each box. Here's an alternative packing plan for the Heinzelmannchen set.