This video explains how to construct the crystal structures of clinojimthompsonite and chesterite using TotBlocks, a series of 3D-printed building blocks. These non-classical biopyriboles were discovered as a result of the predictions made by modular mineralogical theory, proposed by Jim Thompson. Clinojimthompsonite’s structure consists of triple-chain-width T-O-T modules connected by pyribole-type linkages while chesterite’s structure consists of alternating double- and triple-chain-width T-O-T modules connected by pyribole-type linkages.