Most of the really great construction sets are rectangular in shape, or they obey rigid angles. Lego, Kapla Blocks, Kinnex, or Zomeworks are fabulous kits that foster open-ended creativity. But they all tend toward very rectilinear structures. ZOOB is the first construction set I’ve seen that encourages organic, free-flowing builds. There are five basic ZOOB shapes centered on a ball-and-socket connection. When you click them together you have full 180-degree freedom in how the connection is oriented, leading to creations that are curvy, complicated, or ones that repeat like vertebrate in a spine, or carbons on a chain, or even amino acids on DNA. I was surprised by how sophisticated you could make the forms; you may need a bit of patience to get complex ones to fit perfectly (note to 8-year olds). In fact the force and precision needed to assemble pieces may be beyond toddlers, but school kids should have no problem. The plastic pieces are largish, unlike lego, so the finished forms can be quite hefty.
Ages 6 and up, 125 pieces
$20 Buy a copy on Amazon