If you're referring to the building blocks used in a specific context, such as in a game or a construction set, the number can vary widely. For example, some popular sets like LEGO have a vast variety of pieces, but basic building blocks typically include just a few standard shapes like cubes, rectangles, and other geometric forms.
In many contexts, if you are hinting at a "low number," it may suggest there are just a handful of fundamental shapes, possibly around 5 to 10. If you have a specific set or context in mind, I could provide a more accurate answer!