Pig in a Poke, Mayan Number, Baldwin Effect

1. Pig in a Poke

I'd heard the expression "pig in a poke" before but I didn't know what it meant. Apparently a poke comes from the French word poque (same root as pocket), and means a bag. Don't buy a pig in a poke means don't buy something without looking at it first. A trick in mediaeval times was to put a dog or cat in the bag instead. The trick would be revealed by letting the cat out of the bag.

2. Mayan Numbers

Mayan numbers were constructed using dots (representing 1), dashes (representing 5) and a shell-like symbol which was a placeholder, used like 0 in 103 to indicate that 1 represents 100 rather than 10. It is partially a base 20 system although not quite. For example,

   .
   -       1+5=6 which is multiplied by 18 x 20 x 20

  . .      2 which is multiplied by 18 x 20

   -       5 which is multiplied by 20

  ...      
   _
   _
   _       5+5+5+3=18 (units)

is the number 6x18x20x20 + 2x18x20 + 5x20 + 18 which is 44038.

3. Baldwin Effect

The Baldwin effect is when a learnt behaviour evolves into an inherited instinct through natural selection.