A lot of variables there. Most patterns came from another in some way shape or form, either by technique, materials, reference or just plain inspiration. That includes most "originals". You also have intent or knowledge of an earlier pattern.

Today, a lot of information is readily available. But 10-20 years ago the internet wasn't what it is now. So you often had regional patterns that would be very similar, but the parties knew nothing of each other.

Then you have the question of...does the alteration or change make a significant change to the trigger of a given pattern? If it does, should it then be the "Improved Blah-de-Blah"?...remain "Joe Schmucks Blah-de-Blah"?...Or can it then be renamed "Heimy Goobsteins Big Blah-dascious"?

But, you kicked the can over...which ones bug you?