10 rows of 3 solution
Can you arrange 10 coins into 10 rows of 3 coins each?
Gerard Desargues proved that given a point (4) exterior to a
triangle ((1),(2),(3)), and given any three points (5),(6),and (7),
along the line segments ((1),(4)), ((2),(4)), and ((3),(4)), then
the points of intersection of the lines ((5),(6)) and ((1),(2)),
((5),(7)) and ((1),(3)), and ((6),(7)) and ((2),(3)) are colinear: (8), (9), and (10).
Jon's soluton:
Woja's soluton:
Vadim's soluton:
Giri's soluton:
Giri's soluton that only uses 9 coins: