Thank you everyone for your advice and thank you MTS for the link.
I will try to work with what I have, and I will certainly show my result here on the board. I'm planning on doing a fractured quilt, so it should work with me cutting the panels and putting them together again differently in order to get the panels I wanted. It's going to need way more planning and careful thinking, though. And I fear the danger of cutting mistakes is much bigger than if I'd started out with four correct panels to begin with. But we'll see.