Poka Yoke or fooled proof is one of lean thinking's tool, which is originated from Toyota Production System. The tern of Poka Yoke was defined in the 1960s by Shigo Shingo and the aim of Poka Yoke is to reduce the human error in the production line by designing the process to be able to detect by an operator that the operator forgot to finish some element of work in his process. Then after applying in the production line, Poka Yoka was applied in desing process to prevent the user to use the product in the wrong way
For instance, in the first picture, the plug does not design to seperate the prise, which has different size, as a result, a user might be able to use plug in the wrong direction, which leading to the safety issue of the user, while for the second picture, the plug design to seperate the prise, as a result, the user cannot use the plug in the wrong direction, consequently, it will increase the safety of user. In conclusion, Poka Yoka is an important tool to reduce the rework or defect product in the production line and to make the product, whicng considering about the user.