Flag for WTF

Flag for LOL - letter 'L' letter 'Oh' letter 'L'

The metric letter flag for LOL is composed of the colours red, orange, and blue.

Flag for 3.14 - Pi Estimate Flag to the 100ths Place

This metric flag represents 3.14 or Pi to the 100ths place.  The yellow field with blue star represents 3, the brown field with an orange field represents the decimal point, the red field with white star represents 1, and finally the green field with a yellow star represents 4. 

Metric Number Flag for 420

Metric flags are logical numbered flags.  In the three digit case three stars indicates three digits of value. A green field with a yellow star represents 4, an orange field with a black star represents 2, and a white field with a black star represents Zero.  Thus this is the flag for the #420.

Flag for 5O or "Five-Oh"

The 5-O flag is composed of the colours blue and red.  Since blue is the 5th colour rainbow, the blue area in the beginning represents 5.  Since 'O' is the '15th letter in the alphabet it is composed of the first and fifth colours of the rainbow which are red and blue.  In our case the fly diagonal side represents the flag coloured letter 'O'.  Coincidentally US police units flash red and yellow lights on their vehicles when they are in pursuit. 

Flag for 86 - Getting 86'ed

You can declared something 86'ed or become 86'ed from an establishment - namely kicked out or banned from entry.  Now you can wave a flag to indicate the state of being Eighty-Sixed.  In the restaurant biz, instead of saying you're out of something people were 86'ed on onion rings or other type of food.

Metric Number Flag for 10191 - from the Dune Movie

The number 10,191 is mentioned in the 1984 sci-fi classic Dune.  It is during this year that the crap hits the fan and chosen one of the galaxy arises. Here is the Metric Number flag for this year.  It is composed of the colours red, white, pink, black and blue.