Late reoperations after repair of tetralogy of Fallot

A stackable lid for a container includes a main body having an interior portion circumscribed by a lip. The interior portion has a plurality of raised surface features, a plurality of channels, and a plurality of connecting bridges formed therein. A plurality of bosses extend from the interior portion of the main body. Each of the bosses includes a plurality of sidewalls. At least one support feature depends from an interior surface of at least one of the bosses.