My brother uses a 100 foot long, 12 gage, extension cord with his
electric lawn mower. The cord always becomes VERY twisted. They
only last two or three years before he has to replace them.

Is there some type of cord or an adapter that will prevent the cord
from being twisted? (I have seen adapters that claim to prevent
telephone handset cords from being twisted.)

My brother thinks that a flat cord might last longer than a round
cord. Is this true? Thank you in advance for any help.
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When I am in the kitchen, I often kick one of my cat's balls.
After I kick it, he will sometimes play with it for a few
seconds to several minutes. His favorite are the ones that
rattle. He'll play with any ball that makes noise.