This began when I wanted to cover the open slot on the end of the X-axis. While poking around in the Related Models area, I came across Owl Art's X-Axis Labels. I modified the holder portion in Tinkercad, adding enough on the “end” to cover the slot. Then I wiped out the letters on the Customizable Text Sign. I downloaded and resized the Open Source symbol, choosing to make is see-thru; I'll print others whenever a whim overtakes me. Thank you Owl Art for the inspiration.