The patch may get bigger over a period of months and form a sore.

A patch may form into a canker and eventually kill the limb or main branch.

Two clear patches formed on the bottom of the windshield and slowly spread upward.

I can fit the uniforms while the patches are forming.

I stared ahead at the brightening day and wondered behind which patch of blue radiance the dark shape was forming.

And sometimes large patches form and may be uncomfortable.

Now, if you were on the Space Shuttle, the patches wouldn't form a thick layer, they'd just stay all jumbled up.

But at a distance, the random patches of oil form a building's edge; move further, and a weak sun hangs low in the horizon.

The bright white patch formed an idle target.

The moustache and the patch formed a very effective disguise.