proper link: https://medium.freecodecamp.com/how-to-over-engineer-a-door-lock-863b5d58dd0d https://medium.freecodecamp.com/how-to-over-engineer-a-door-... (dou

proper link: https://medium.freecodecamp.com/how-to-over-engineer-a-door-lock-863b5d58dd0d https://medium.freecodecamp.com/how-to-over-engineer-a-door-... (double-pasted, looks like)