retractable utility knife

This is a magnet rubber band retractable utility knife inspired by the “Zero”, https://www.kickstarter.com/projects/riverycnc/zero-a-deceptively-simple-knifeI thought it was funny so I made my creation. This knife requires additional parts:1, one ½ inch rubber band (tiny rubber band)2, two 5mmx3 magnets3, one utility blade