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A math problem which a child can understand. But who can solve it?
https://protokol2020.wordpress.com/2017/01/29/a-topological-problem/
Tvira gung pbhagevrf ner nyybjrq gb zrrg ng gurve pbearef V oryvrir gur fbyhgvba vf avargrra pbhagevrf, naq V pna cebir vg ba bar fznyy pbaqvgvba.
Yrg gur ahzore bs a-ghcyl ynaqybpxrq pbhagevrf or nv sbe v terngre guna be rdhny gb mreb, n0 orvat gur ahzore bs pbhagevrf ba gur pbnfg. Fvapr pbhagevrf ner nyybjrq gb zrrg ng gurve pbearef vg'f rnfl gb znxr n znc jurer nyy a-ghcyl ynaqybpxrq pbhagevrf zrrg nyy gur (a+1)-ghcyl ynaqybpxrq pbhagevrf (sbe rknzcyr unir nyy pbhagevrf orvat pbapragevp evatf, naq gura sbe rnpu a unir n "cvapu" jurer nyy gur a-... (read more)