Yes and No.
Apple made an iPod, which is a portable mp3 player. Sony also makes portable mp3 players, along with hundreds, if not thousands of other companies. Totally legal. They’re just mp3 players. Heck, they’re all mp3 players with screens, headphone ports, controls, using the same type of internal memory. Very similar when you break it down.
If the backpack were a very very very specific purpose, for example…
A woodland firefighters backpack that has a hydration bladder and the ability to carry a burn victim out of the woods, made from some very specific material, handmade in the USA.
Would another company be able to make a backpack that does this same exact thing, out of the same exact fabric, and in the USA?
The answer is Yes.