This is a Free/Busy Sign with a cover and slider to switch between the two.

Assembly

After printing the three pieces, place the lid inside the base and then glue the cover on top of the base to lock the lid in.

Customization

There is enough space to fit a printed alternative background to dynamically adapt it to your daily needs. The size of the paper for a good fit should be:

• width: 97mm
• height: 45mm

I split it into three columns (44mm, 6mm, 44mm) and used the middle one as a spacer.