Of the different possible sources of defects, what sources do pokayoke address?

Pokayoke is Japanese for “foolproofing.” For example, suppose a source of equipment breakdown is the operator forgetting to check the level in the lubricating oil reservoir. When the oil level is too low, the shaft on the machine freezes. As a result, the cutting tool is damaged and the part being machined is destroyed. A simple, inexpensive foolproof device is a float in the oil reservoir connected to a light and a switch. When the oil drops to a certain level, the light goes on and the switch prevents the motor from being turned on. Most pokayokes are inexpensive and originate from worker suggestions.