As children, most of us would have constructed shaky fortresses out of pillows, mattresses and mom's best manchester. In the eyes of Illinois-based product designer Brian Lilly, these childhood constructions could benefit from a little more structural stability so he developed Buildies, a kit of cardboard blocks and connectors designed to teach kids about engineering, all while letting their imaginations run wild.

The jumbo-sized Buildies blocks are designed to interlock thanks to Lego-like bumps protruding from the top. Using both four plug and smaller, single plug blocks, kids can construct anything from the impenetrable walls of a castle to stages for their puppet shows.

The kit comes with pieces designed specifically for the roof, because we all know the best forts provide some form of shelter. These cardboard trusses use plugs on the underside to lock into place when sitting atop the walls. They are also adjustable, with a cardboard "crossbeam" to slide into one slot for a medium angled roof, with another slot allowing for a high angled roof when the kids get a little taller. Included are also block connector strips, which act as the "mortar." Placing these over the plugs in-between layers provides extra stability, overlapping conjoining blocks to hold them together.

While the dull grey color may seem uninspiring at a glance, Lilly claims this was intended to make Buildies gender neutral, with marker-wielding boys and girls encouraged to decorate the blocks as they see fit. Lily also says that the materials are made from recycled cardboard and can be dismantled, folded up and stored away when playtime is over.

Lilly has taken Buildies to Kickstarter to raise funds for commercial production. Kits vary in size and price from the 24-block, US$65 Theater Kit, to the 224-block, $600 Great Wall of China. He plans to begin shipping the his cardboard bricks and mortar in July 2014 if all goes to plan.

Lilly gives an overview of his creation in the pitch video below.

Source: Buildies