Apple has tested at least 3 different styluses for the iPad

Apple has previously tested multiple prototypes for a stylus intended to work with the iPad, a former Apple engineer who requested to remain anonymous told Business Insider.

At least three different stylus prototypes were present at Apple about four years ago, this person said. Details on these test models were scarce, but this person described the prototypes as "different approaches to the stylus."

"I never saw them, but I know they existed," said this former employee, who was close to people who had worked on the prototypes.

We also heard from this person that prototypes for a larger iPad were present at Apple around this time, which would line up with our previous report that Apple has been testing an iPad with a bigger screen for at least three years.

"The people that worked on it never learned why none of them ended up in production," this person said in reference to the stylus prototypes. "They were told to work on something and then it was taken away and they didn't have any idea."

Apple has been rumored to be developing a stylus for the iPad for quite some time. KGI Securities analyst Ming-chi Kuo, who has an excellent reputation when making predictions about upcoming Apple products, said he believes Apple is working on a stylus to be released this year. The company also has numerous patent filings for stylus designs.

This doesn't necessarily mean Apple has plans to release a stylus - it just suggests the company has considered the idea strongly enough to patent it and create some prototypes. Large technology companies like Apple experiment with different product ideas all the time with no guarantee that they will definitely come to market. Steve Jobs famously detested the idea of a stylus, saying the following at the iPhone OS 4 event in April 2010:

"It's like we said on the iPad, if you see a stylus, they blew it."

But in recent months, Apple has been adding various improvements to the iPad that make it more suitable for productivity. When iOS 9 is released in the fall, for example, you'll be able to use split-screen multitasking with certain apps. Many are expecting Apple's much-rumored 12.9-inch iPad, which will reportedly debut this fall, to bring new use cases to Apple's tablet. Adding a stylus could be one way to do that.

Apple has declined to offer comment for this story.