Abstract: A child building block is provided having a collapsible structure that is formed of a flat sheet material and is erected into a cuboid shape having connector elements to remain stable and for adjoining adjacent building blocks during fort construction. When the sheet material is connected and the block is erected, the block forms an upper surface having a pair of upstanding protrusions thereon, a pair of side walls, and a pair of end walls that are perpendicularly attached with an open lower. Adjoining edges of the block are secured using a simple push tab and tab receiving area. The upstanding protrusion of the block upper surfaces fits within the open lower of a corresponding block member positioned thereover. Finally, adjacent blocks can be aligned with one another and secured together, allowing construction in a grid pattern.

Abstract: A child building block is provided having a collapsible structure that is formed of a flat sheet material and is erected into a cuboid shape having connector elements to remain stable and for adjoining adjacent building blocks during fort construction. When the sheet material is connected and the block is erected, the block forms an upper surface having a pair of upstanding protrusions thereon, a pair of side walls, and a pair of end walls that are perpendicularly attached with an open lower. Adjoining edges of the block are secured using a simple push tab and tab receiving area. The upstanding protrusion of the block upper surfaces fits within the open lower of a corresponding block member positioned thereover. Finally, adjacent blocks can be aligned with one another and secured together, allowing construction in a grid pattern.