With 4th of July coming up I designed a flag to celebrate. I would be easy to turn this into a fridge magnate, or if you print it in PETG you could use 3M tape and attach it to your vehicle. 

Feel free to scale this however you need. 

It does require you set up color changes. Start with blue then change to white and finish with red.

Its only 1.5mm thick at the top most layer so depending on how you intend to use it, you might have to scale on the z