Step 3: Writing the Codes
I like writing individual letters on the back of each piece, but you could also make really big letters/numbers that go over multiple pieces. Keep in mind, however, that making large numbers may provide the recipient with another way of piecing the puzzle together.
Skip a piece in between letters/numbers of the gift card codes. This prevents the recipient from collecting all the pieces with writing on them and trying to only assemble those few pieces.
Codes can be written horizontally, vertically, or even diagonally, just be sure to properly mark the beginning and end of the code for the recipient.
The best way to write the codes is to flip the entire puzzle, but that may be unpractical.
Instead, you can flip individual pieces and write on them - just be sure to orient your code so it's going the right direction. For example, if turn a row of pieces upside down, be sure to write the code from right to left instead of left to right.
I always start my codes with a number, star and/or arrow, just in case i get confused.
I also write random messages in different areas of the puzzle for fun and to maximize the percentage of pieces with writing on them.