Easy to Make "green" Tablet PC/calculator

1take a paper board box possibly one previously used to package orange cream sickles.
2gradually open it up being careful not to disintegrate it into shreds if you happen to be a hot chick with large talons.
3fold over to expose a cleverly kept secret calculating surface which a trusted pen or pencil (sold separately, while supplies last) can use to compute calculus algorithms for making your own qr codes from scratch. the amazing thing is it uses no additional electricity besides indoor lighting to see and even that migh be avoidable if glowing ink is used.
4get ready to have a truly portable and always on green computer for next to nothing (offer void where prohibited by state law).