I still remember a low-tech theft prevention device my friend invented for personal use. He stuck a 100 or so needles into a cushion and upon leaving the car he

I still remember a low-tech theft prevention device my friend invented for personal use. He stuck a 100 or so needles into a cushion and upon leaving the car he'd leave the cushion on driver's seat with needles' tips facing upwards. From the outside it looks like a normal cushion but if a thief is to sit on it...