Turing Machine remembering copied symbols
Once you've hit the '&amp;' separator, move left until you see the '#', then move one cell to the right and replace the '1' with an 'x' (and change to state $p$ to "remember" you've seen a 1) or a '0' with a 'y' (changing to state $q$ to "remember" you've seen a 0). Now move right until you pass the '&amp;' separator and see a '#'. Replace that with a '1' if you were in state $q$ or with a '0' if you were in state $p$. Now move to the left until you see a 'x' or a 'y', move one cell to the right and repeat what you've done before. Continue the process until everything on the left is a string of 'x's and 'y's, then make one more pass, restoring the values to their originals.