one sided shape
thingiverse
I was having fun one day and made this shape that if you trace the side, you will find that there is only one side
Download Model from thingiverse
With this file you will be able to print one sided shape with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on one sided shape.