Informer can be useful for your car. In it you can display your phone number and put under the car window. If your machine will interfere with the passage, you will be contacted and you'll avoid trouble.
Widget is conveniently mounted on the wall with screws. It is designed as a smartphone Samsung Galaxy S7 Edge. You can show it to 2 phone numbers.
Part 1 of 2. Watch the second part here:
https://www.shapeways.com/product/985TFXRN9/the-numbers-for-the-phone-number
Bonus: https://www.shapeways.com/product/5BBTBERUH/symbols-letters-numbers