#160.
X(10 AD-70 AD) was a Greek mathematician and engineer who was active in his native city of Alexandria. These are X's inventions:

• The first vending machine was also one of his constructions, when a coin was introduced via a slot on the top of the machine, a set amount of holy water was dispensed. 
• In optics, he formulated the Principle of the Shortest Path of Light. It was nearly 1000 years later that Alhacen expanded the principle to both reflection and refraction, and the principle was later stated in this form by Pierre de Fermat in 1662.
• Today, X's name is most closely associated with X's Formula for finding the area of a triangle from its side lengths.

ID X.