Co and counter flow heat exchanger

Airfoils and methods of cooling an airfoil are provided. The airfoil may comprise a spar; a coversheet on the spar; and a dual feed circuit between the spar and the coversheet. The dual feed circuit may include a first dam, a second dam spaced apart from the first dam along the chord axis of the spar, a first inlet disposed adjacent to the first dam, a second inlet disposed adjacent to the second dam, a circuit outlet disposed between the first inlet and the second inlet, and a plurality of diamond and/or hexagonal pedestals disposed on an outer surface of the spar. The diamond and/or hexagonal pedestals may form a plurality of cooling channels between the first inlet, the second inlet, and the circuit outlet. There may be no other circuit inlets are located between the first inlet and the second inlet.