I'm with KP91,
In addition it's extremely difficult to come up with an original concept, pretty much everything under the sun has been done already somewhere especially ugly and or useless things. If you care to narrow the parameter everyone steals/borrows.
Corporations duplicate 95+% of an item then change color, and or footprint or materials, something to avoid patent infringements.
However as previously mentioned if you're cloning an item for personal use, for =0= monetary gain I see nothing wrong with it.
If one takes a design "concept" and modifies it enough to give it individuality, like making it better it's good to go to the market.
I didn't invent wood but I use it all the time and claim ownership of what comes out of it because I make it mine.
Never bite the hand that looks dirty!
The more you know the more you're worth