This more of a proverb but we'll go with it anyway.
Apart from watching the President's funeral today, I've been walking the dogs.
We have two rescue dogs; Sherry and Sortudo. They're very old and very stupid and I'm not sure which is the oldest or most stupid as neither respond well to instruction.
Well, you know what they say, 'you can't teach an old dog new tricks.'
Of course, you can an apply this to people too so maybe I'm the oldest and daftest of the lot!
Here's how to train a dog or maybe a human. Sounds like it's recorded on a motorway but you do get English captions too so it's really helpful. Just stand and stay. Good dog!