Abstract: A safety enclosure building system, includes a first wall panel that is rotatably mountable to a first wall, and a second wall panel that is rotatable and slidably mountable to a second wall; such that the wall panels are configured to prevent penetration of a projectile of a firearm; such that the safety enclosure building system is configured to be positioned in a folded-in configuration in a corner between the first wall and the second wall; and such that the safety enclosure building system is configured to be folded out to a folded-out configuration, such that the folded-out configuration can enable students to seek safety in a safe interior behind the safety enclosure building system.

Abstract: A modular building system, includes a modular building assembly, including a base mounting structure with first and second base angle brackets; a left receiving wall assembly, including a left primary wall assembly, and left front and left rear corner brackets; a right primary wall assembly, and right front and right rear corner brackets; and front and rear wall assemblies; and a platform with legs; such that the modular building assembly is positionable on a top surface of the platform.

Abstract: A modular building system, includes a modular building assembly, including a base mounting structure with first and second base angle brackets; a left receiving wall assembly, including a left primary wall assembly, and left front and left rear corner brackets; a right primary wall assembly, and right front and right rear corner brackets; and front and rear wall assemblies; and a platform with legs; such that the modular building assembly is positionable on a top surface of the platform.

Abstract: A modular building system, includes a modular building assembly, including a base mounting structure with first and second base angle brackets; a left receiving wall assembly, including a left primary wall assembly, and left front and left rear corner brackets; a right primary wall assembly, and right front and right rear corner brackets; and front and rear wall assemblies; and a platform with legs; such that the modular building assembly is positionable on a top surface of the platform.