Blocks in SOLIDWORKS offer a quick and efficient way to reuse sketch geometry, helping designers speed up repetitive tasks. The demonstration shows how to turn a completed sketch into a block, save it into the design library and then drag it into new parts whenever needed. A logo example illustrates how a stored block can be used to cut features into a model. The walkthrough also explains how to edit an existing block by exploding it, adjusting the sketch and saving a new version, allowing variations to be created while keeping the original intact.