How perfect are these squares??
9:05
Two from Malaysia
13:54
What flag is this??
12:25
Piano Sonata No. 19 In D Major, Kv 576
20:14
Irish Math Olympiad | 2009 Question 3
13:57
Make it look like a simple calculus problem.
14:27
I usually skip inequalities...
16:36
a divisibility puzzle from Croatia.
12:10