Picture of the week: a Sangaku
This five-meters long triple tablet was hung in 1797 in the Onnma shrine in the Aichi prefecture (Japan) and contains 30 problems. It is called a Sangaku, a mathematical ex-voto representing solved geometrical problems. A book about Sangakus is forthcoming, Sacred Mathematics: Japanese Temple Geometry.
What do our friends interested in the anthropology of maths (Christophe, Helen, Hugo…) think of this interplay of religion and geometry? As for me, growing up in catholic Brittany, I have seen my share of weird ex-votos (the last one on my list was this toy boat, last June), but this tops everything else…
(found on Science News).