Since their invention in 1900, reflector sights have come to be used as gun sights on all kinds of weapons. They were used on fighter aircraft, in a limited capacity in World War I, widely used in World War II, and still used as the base component in many types of modern head-up displays. They have been used in other types of (usually large) weapons as well, such as anti-aircraft gun sights, anti tank gun sights, and any other role where the operator had to engage fast moving targets over a wide field of view, and the sight itself could be supplied with sufficient electrical power to function. There was some limited use of the sight on small arms after World War II but it came into widespread use after the late 1970s with the invention of the red dot sight, with a red light-emitting diode (LED) as its reticle, making a dependable sight with durability and extremely long illumination run time.
did they have red dot sights in ww1?
OPTIONS:
- no
- yes
+++++
Answer: no

More famously, Harley-Davidson attempted to register as a trademark the distinctive ''chug'' of a Harley-Davidson motorcycle engine. On February 1, 1994, the company filed its application with the following description: ''The mark consists of the exhaust sound of applicant's motorcycles, produced by V-twin, common crankpin motorcycle engines when the goods are in use.'' Nine of Harley-Davidson's competitors filed oppositions against the application, arguing that cruiser-style motorcycles of various brands use the same crankpin V-twin engine which produces the same sound. After six years of litigation, with no end in sight, in early 2000, Harley-Davidson withdrew their application.
does harley have a patent on their sound?
OPTIONS:
- no
- yes
+++++
Answer: no

Puerto Rico (Spanish for ''Rich Port''), officially the Commonwealth of Puerto Rico (Spanish: Estado Libre Asociado de Puerto Rico, lit. ''Free Associated State of Puerto Rico'') and briefly called Porto Rico, is an unincorporated territory of the United States located in the northeast Caribbean Sea.
is puerto rico part of the united state?
OPTIONS:
- no
- yes
+++++
Answer:
yes