As we all know, each and every number belongs to different categories.
Some of these groups are restricted to the game of roulette.
The author of "Born on a blue day" must disagree that 7 is a red number.
After playing too much roulette you may enter other areas of Life and get frustrated
as you discover that 7 is not always red
Today an idea struck me: The idea of wagering double streets (1-6, 4-9 etc.) that have ONLY appeared with EVEN OR ODD numbers. Not both.
The same simple method might be tried on carré (square or corner) or street.
I really don´t know which is best. Tests might give you the answer.
My deadline: Seven sleepers in area 1-36, i.e. exactly seven numbers that have not appeared;
and I prefer masse égale (flat betting).