In the world of Apple rumors -- a strange demimonde that can frequently be observed feeding on itself -- the favored topic of the moment appears to be the screen size of a couple of upcoming devices.

So what are the rumors? Bigger or smaller?

Well, both actually. Apple is working on a new smaller-screen iPad, the rumoristas proclaim, while the next generation of the iPhone will have a larger screen.

Let's start with the iPad. One tech writer claims to have seen a prototype, and media reports from South Korea, China and Taiwan, say Apple has ordered Samsung screens that are 7.86 inches diagonally.

That would make for an "iPad mini" considerably smaller than the current model with its 9.7-inch screen.

With the existing iPad selling in numbers that make analysts' heads spin, why would Apple want to make a smaller one?

While no competitor has managed to sell tablets in the iPad's size range with any success, some smaller, cheaper tablets -- Amazon's Kindle Fire being the most visible -- are gaining traction with purchasers, as are some other Android-running tablets from other manufacturers.

Also the iPad, while undeniably portable, is a bit big for many handbags and certainly any normal size pocket, whereas a smaller, svelte iPad might work.

However, a smaller-screen iPad -- particularly anything smaller than the rumored 7 or so inches -- would have the iPad heading toward the smartphone world, where screen sizes have been getting bigger.

Which brings us to Apple rumor, the sequel: the next iPhone, it says, will ditch the current 3.5 inch screen it's sported since its introduction for a larger screen -- 4 inches, so the speculation goes.

With smartphone screen sizes showing a trend to bigger acreage, from an average 3.2 or 3.5 inches to as much as 4.7 inches, Apple must step up or be seen as being mired in a "retro" period of smartphone design, the rumors say.

There's even the Samsung Galaxy Note, with a 5.3-inch screen that has some calling the device a phablet.

There's less to go on for the iPhone screen rumor -- no one's seen a prototype and Apple hasn't signed up with screen manufacturers for anything even suggestive of an iPhone re-model in terms of display real estate.

There is a stumbling block for Apple if it wants to compete with Android phones and their ever-larger screens, however, and is has to do with apps.

Android apps for the most part are designed to fit into many different screen sizes, in the same way Web sites display the same on different size computer screens.

Apps written for Apple's iOS, however, are all designed for the 3.5-inch screen.

If Apple were to increase the screen size and/or its resolution, developers could be faced with creating two versions of their apps to continue to run on both the original and a larger screen.

So the bigger iPhone seems on the face of it less likely than the smaller iPad, but it all is likely moot because of the one fact that remains: Apple never deigns to make comments on rumors, preferring to simply go about its business until it's ready to unveil a new product.

So the world will know for sure about a smaller iPad or a larger iPhone when Apple is ready to announce such a device -- and not a minute before.

No rumor, that.