If you're in the need of a quick gift box this could be your solution. And is super easy to make.
Step 1: Score
Take your 12x12" paper and score at 3" and 9". Rotate your paper and score at 1", 3 1/2", 6 1/2" and 9".
Here is a template as well to see how it should look like.
Step 2: Cut
With the 1" score line facing you cut away the corners down to the 3 1/2" mark, then cut further towards the 6 1/2" score line. Rotate your paper and cut towards the first score line.
Step 3: Fold & Burnish
Fold and burnish all the scored lines.
Step 4: Assemble
Lift the side flaps and adhere everything using double-sided tape or glue if you'd prefer.
Step 5: Finish
Round the corners of the lid.
You can close the box either by tucking the lid inside or fixing it into place with a sticker.