I had two thick upholstery-type fabric samples, in bright red and navy blue check, and I thought they would work well with the Thomas the Tank Engine scrap pieces.
As the cardboard was around the edges, I thought maybe it was okay to leave it in to give it even more stiffness. It was a bit hard to sew through neatly, but it worked out okay.
I had two extra Percy the Train and Fat Controller scraps that didn’t make it onto the art portfolio, so I decided to put them on either side of an extra little pencil case to go with the portfolio.