This is a sliding letter changing sign that I made! All done in Solidworks and Adobe Illustrator. I have a video linked down below on the whole process of making it if you're interested.
Be sure to print 3 of the retainer pieces and 2 of the suction cup pieces! Just one of everything else.
Feel free to modify this!
Glue and Suction Cups
In order for this thing to operate, you have to glue on the three retainer tabs after the plates are held together. This not only limits the left and right sliding distance, but also sandwiches everything together. The suction cup holders also have to be glued onto the back, and make use of the smallest suction cups I could find at my local Walmart.