It's nice surprise when opening the iris box, to see the heart with the names of two love birds. Change it to your name and your Valentine for a Valentine's Day gift. Edit the simple OpenSCAD design to create your custom version.  Print at 0.2 mm layer height. Change filament color at Z layer 1.8 mm and at Z layer 12.8 mm.

After printing cut the 16 little tabs on the bottom to free the four iris lens flanges. After printing insert a flat screw driver between the base and the outer shell to break it free from the base. Work the flat screw driver all the way around 360 degrees cracking the base free as you go, but being careful to not mar the plastic. The operation might be rough at first, but it quickly becomes smooth the more you open and close. For extra smooth operation lubricate with “dry lube with Teflon.”

This is a variation of LoboCNC's wonderful "Print-In-Place Iris Box (locking).  The variation, called irisbox-locking+additions.stl, contains longer pegs so that the iris lens flanges will not fall off. The variation also includes internal supports, so that the base of the outer shell prints more reliably. When post processing, it's those internal supports that you are breaking with the flat screw driver.