Would Somebody Please Invent This.

I really like working in spiral notebooks (as opposed to binders). I like using both sides of the paper, too. But when you're doing math and you need to copy your work from the end of the right page to the back of the same page, it gets really annoying to not be able to lay the two pages side by side to copy the last line of work, especially in economics where there are piles of variables with little subscripts, wiggles, and hats that you have to rewrite exactly correctly. Something like a scroll would be perfect for this, but not so perfect in other respects (like looking up something you did a long time ago). Can we do better?