けん
かぎ
None
You take some gold and cover your yoga brush in it, turning it into a key. You shove the brush you normally use for yoga into the lock to your car and pour the gold over it. Now it's the right shape to be a key!
This key has to be perfect, because if it isn't the car guillotine (かぎ) will come down and chop off your hand!
Currently there are no similar looking kanji which exist in the WaniKani learning system