Spent too long being puzzled, doing a lot of complicated: if this, if that type stuff.
Then read your article on Bill Gates and had an aha moment.
Great fun once you have solved it &

until you have.
Luckily I solved it after about 1/2 an hour (and some research

) otherwise a guaranteed cause of insomnia and sulking, I would have thought.
Many thanks for making my brain take a step sideways as it has refreshed the thought processes again