A formed core comprising a first and second plurality of pyramidal frustum bases, the first plurality of pyramidal frustum bases extending in a first direction and the second plurality of pyramidal frustum bases extending in a second direction, and wherein each pyramidal frustum base comprises: a node comprising a convex regular polygon, the convex regular polygon comprising a plurality of sides oriented in a first plane and wherein each side of the polygon of the node of each of the first plurality of pyramidal frustum bases is parallel to a side of the polygon of the node of at least one of the second plurality of pyramidal frustum bases; a plurality of faces extending from each of the sides of the polygon of each node of the first plurality of frustum bases to a side of the polygon of each of the second plurality of frustum bases.