The cabinet was made as a wedding gift for my son and daughter in law. The cabinet itself follows conventional design and construction techniques - what makes the anniversary cabinet different is the combination locking mechanism. The four drawers require you to know a code (combination) in order to open them. Each drawer has a different combination. The idea then, is to give the combination for one drawer at a time (on the wedding anniversary). To get things going though the combination for the first drawer (the bottom one) is given "free" at the time the gift is presented so that the general operation can be explained and tested. In this case the guests at the wedding reception were given a sheet of paper and an envelope so that they could write a note to the bride and groom. The envelopes were sealed and placed at random in the top three drawers. So on the anniversary when the combination is revealed the contents (envelopes or other gifts) can be accessed. Of course this may not work as intended, as the level of bribery re getting the combination early could come into play.
The video below shows how the combination locking system works and the Steps following the video give details on the construction of the cabinet and the locking system.