| Hints | Inventions |
| Was invented as early as the 6th Century BC | |
| Appeared Early in the 7th Century in the reign of the Tang dynasty, and required lots and lots of blocks | |
| Invented in 105 AD, it is not known who the exact inventor was | |
| Business records show huge Roman imports of _____ | |
| Invented by Taoist alchemists to pack a punch | |