ceiling or back seat design

[Grip72]

Hey i just saw a picture of a truck that someone made a giant "X" on the cieling out of puffy carpet or something i thought it looks sweet. I want to attempt to make one for my car. I have the vinyl stuff on my cieling and its a gray color, does anyone have any idea how to make a design, say a maple leaf or something...i dunno..and apply it so it stays on the ceiling. I was also thinking of making a design on the middle back seat, how would i do that? Any ideas/suggestions is greatly appreciated..thanks alot