اما رنگی مثل آبی، که ساختنش خیلی سخت‌تر بود بسیاری از تمدن‌ها خیلی بعدتر فهمیدن چطور اون رنگ رو خودشون بسازن. 
But a color like blue, which was much harder to make -- many cultures didn't begin to learn how to make that color until much later. 