For a more decent jeans, khakis or corduroy pants, you'll need 4 pieces plus another 2 or 4 pieces for pockets. For this specific project, i'd followed DANA M.A.D.E project tutorial here
And here is my version.
Using 100% cotton corduroy found here.
And here is the close-up lining inside the pocket. I am using white cotton from Ariz's recycled shirt.
The baby boy in action :)