In the maker's words
The HZ 5-15 Cast Padlock is designed in the shape of a padlock and is quite challenging to open. It consists of two elliptical pieces that are tightly locked around circular pieces, and it takes work to separate them. The designer of this puzzle is JinHoo Ahn from Korea. The puzzle's theme is "obstinacy." So, keep trying to separate and put the pieces back together until you can unlock the puzzle.
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