I suspect, all else being equal, that laundry will dry faster when the lines are parallel to the wind than at right angles. Reason: The wind speed is less obstructed, so that when, at the ambient temperature, water molecules evaporate from the cloth, they are swept away quickly and are less likely to return to the cloth through diffusion, than when the wind speed is more obstructed. Arguably, if the wind speed is high enough that the clothes stands out almost at 90 degrees to the vertical, it will make little difference. However, for lesser winds I think I am right. One complicating factor: the direction of sunlight. If you have anything resembling a clear day, the clothes position will affect the solar cross-section substantially, which would be the most important facter in those conditions.