How do i know if its my pattern or not.

[Tubbychook]

I have used other patterns as a rough guide to help me develope what i think is my own pattern to make pocket and fitted nappies but im just wondering is it really my pattern.
I feel that altough it is one that i have drawn up it looks very much the same as all the other nappy patterns out there and it gets sewn together much the same way. The biggest change i made was the wings i wanted square ones so i made them square.
Is this enough to make it my own nappy or not. Also if it is being snapped does the placement of the snaps make it my own. I eventually want to be able to sell them at the flea markets but i dont want to breach any copywrite laws.

[mumma bear]

I am not really sure how that all works with copyright etc.
I made my own pattern and it was completly from scratch i have never even seen a commercially available pattern and started drawing mine up before i even owned 1 MCN so it is definately mine, one of a kind. I am up to change 9 so it has needed some modification along the way, but i now have what i consider so be a very good nappy for my DS.

I am sure there will always be similarities with sewing techniques but i am not sure to what extent it needs to be different to be your very own.

Sorry i can't help more.