Telling kids about engineering is kind of like trying to explain quantum physics to your goldfish. But show a kid how to use engineering in a  fun way and they’ll never forget those “lessons.” Product designer Brian Lilly came up with a beautifully simple and effective way to teach kids the finer points of engineering through something every kid loves: building forts.

Lilly’s invention is called Buildies. The main part is big blocks that look like giant-size Lego bricks. They have protruding bumps on the top and matching cavities on the bottom, allowing them to interlock safely. Strips of “mortar” have cutouts that hold the blocks together to further stabilize structures.

Roof modules come with the kits, which is important for the defense of any good fort. The roof pieces can also be used in novel ways – building drawbridges, ship hulls, ramps, or whatever else strikes your fancy. The blocks come in a rather dull grey, but this is an intentional design choice. Lilly wanted to make the blocks gender-neutral so builders of any age and gender would feel like the blocks were made just for them. They are infinitely customizable with markers, stickers, wallpaper – whatever is available.

Because there are no rules or patterns, Buildies can be made into anything at all. They could even be helpful for students or adults who want to build temporary custom furniture without spending an arm and a leg.When you’re done building, every block can be folded down and stored flat. As if we weren’t impressed enough with the idea and the execution, the sight of a makeshift Kool-Aid man breaking through a wall totally won us over. Unfortunately, the Kickstarter project fell just short of its goal, but hopefully Lilly will find another way to bring this product to shelves because we can’t wait to build a castle in the dining room.