In 2008, Pentax filed patents for some lens designs that have an image circle similar to that of the Four Thirds format. There has been some speculation as to what these lenses might be used for.
Some have speculated that Pentax might revive the 110 format, but for digital mirrorless interchangeable lens cameras. This format used negatives of the size 17x13mm (21.0mm diagonal), while the Four Thirds format has an active sensor area of 17.3x13.0mm (21.6mm diagonal). So they are virtually identical. Here is an illustration:
The lens designs Pentax patented were: 17mm f/2.8, 17mm f/2 and 14mm f/2.8. From a Micro Four Thirds perspective, these sound like sensible wide angle lenses.
Some have speculated that these designs were licensed to Panasonic and/or Olympus for use in their Micro Four Thirds lens lineup. To evaluate this, we can take a look at the latter: It has some resemblance to the Panasonic Lumix G 14mm f/2.5 pancake lens. We remember that when Panasonic first announced this lens, it had the specifications 14mm f/2.8. It was later changed to f/2.5.
Comparing the lens design layouts, we see the following:
Are these lens designs similar? I don't really have the right competence to answer this myself, but a simple inspection reveals that they are in fact quite similar. They have basically the same lens elements and groups. So it is not inconceivable that the Lumix G 14mm f/2.5 is based on the Pentax patent. But this is far from concluding evidence.
What about the Olympus M.Zuiko 17mm f/2.8 lens? Could it be based on the Pentax patent for a 17mm f/2.8 lens? Not really, is my guess. Their lens designs differ quite a bit.