Triangulation: What does it mean?

Case

Your company (B) based in Germany purchases goods from a Czech supplier (A) and resells the goods to a Belgian client (C). The goods are transported directly from the Czech Republic to Belgium by the Czech supplier himself (no stop in Germany).

This is a so-called “supply chain transaction” or "ABC supplies" for VAT purposes, a chain of supplies involving at least 3 businesses (A, B, C) with only one physical movement of goods.