For example, if might cost ฿100 million to build the frst copy of a new ariplane, ฿80 million to build the second, ฿64 million to make the fourth ฿51 mililon for the eighth and so on, with the unit cost falling 20% at every doubling of volume before reaching a plateau, say ฿15 million. The planes get cheaper to build as the company learns how to do it more effciently. Workers work faster, make fewer mistakes and waste less material.