avnerium

3 ms·

1. 1.▲
   by avnerium 8y ago

   Or you can form the alternating sum of the bits, e.g. for 0b10011001 you calculate 1-0+0-1+1-0+0-1 = 0 which is divisible by three. (That's similar to the divisibility test by 11 of a number in base-10, or more generally testing if a n
2. 2.▲
   by avnerium 8y ago

   Color the board like this: https://imgur.com/a/kuaeQJW Note that each tromino covers one yellow square, one red square and one green square. Also, there are 21 yellow squares, 21 green squares and 22 red squares, so th
3. 3.▲
   George Orwell's review of Mein Kampf (1940) [pdf](worldview.carnegiecouncil.org)

   3 points by avnerium 11y ago|1 comments