I've turned comments off on this blog as I'm getting quite a lot of spam. I've been able to keep on posting on flickr but haven't the time and energy to manage to be an active blogger. Sorry not to have been visiting your blogs.
My best wishes to you all!
Update: Comments are back on and I'm back!
BrainTwister #91: Balls in boxes
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From New Scientist #3561, 20th September 2025 [link] [link] We have four
boxes numbered 1 to 4 and four balls numbered 1 to 4. How many ways can we
put the...