Note: Do not leave this sign on dishwasher when it is running! Depending on your material, the dishwasher may get too hot and melt your sign. Remove before running the dishwasher.
This is a very simple sign that rests on the top of my Bosch dishwasher to remind everyone else in the house that the dishes are clean, but not yet emptied. While the dishwasher has an LED to show when cleaned, if accidentally cleared then someone may put dirty dishes in with the clean.
This sign rests on top of the door when closed and can stay in place on my dishwasher when the door is fully closed.
You may need to adjust the sizes and wording for your needs, but this is a simple project to see some basic features in OpenSCAD to help inspire you for other projects. By reviewing the code (less than 50 lines!) you can learn a lot about simple placement, including text, etc.