A multi-die building block for a stacked-die package is described. The multi-die building block includes a flex tape having a first surface and a second surface, each surface including a plurality of electrical traces. A first die is coupled, through a first plurality of interconnects, to the plurality of electrical traces of the first surface of the flex tape. A second die is coupled, through a second plurality of interconnects, to the plurality of electrical traces of the second surface of the flex tape.