EXAMPLE: You decide that you want to be able to Produce on 3 territories instead of 2 (ignore the Mill for this example), and you want to decrease the cost of enlisting a recruit by 1 food. By taking the Upgrade action, in addition to paying the oil cost and gaining the coin benefit, pick up any technology cube from a green box (in this case, the Produce action benefit) and move it to any red box with bracketed borders (in this case, the Enlist action cost).