A picture of nerd clock if you search on Google:

Explanation of the twelve:

  1. Legendre’s constant which says prime numbers appears at the rate of ln(n)
  2. Infinite series 1+0.5+0.25+…
  3. ASCII character “3” of code 0x33
  4. Modular exponentiation
  5. φ = Golden ratio constant, [1-sqrt(5)]/2
  6. Factorial(3) = 6
  7. 0.99999 = 1
  8. Binary 0b1000
  9. Base-4 number 21 = 2 4 + 1 = 9
  10. Combination 5C2 = 10
  11. Hex number 0xB = 11
  12. Cubic root of 1728 = 12