Abstract: The restrainer forms an elongate triangular tube with a right angle between a base panel for resting on a resting surface and a vertical panel. The vertical panel provides a child restraining wall, and the restrainer is connectable to other similar restrainers at an angle of 90 degrees to form a rectangular crib area for infants. The vertical panel is collapsible to be flat on the resting surface, and the restrainer can be put in line with another restrainer to form a longer restrainer wall for children of 18 months to 2 years.