Just write the streets down 1-12. Then mark x on where it lands, until you get afew gaps. Next bet those "gaps" placing 6 streets, like this; (example) x= numbers hit, 0=gaps, bets are placed here........
1 2 3 4 5 6 7 8 9 10 11 12
0 0 0 x x x 0 0 0
X
Game1: W
1 2 3 4 5 6 7 8 9 10 11 12
X X 0 0 0 0 X 0 0
X
Game2: LLW
1 2 3 4 5 6 7 8 9 10 11 12 0
X 0 0 X 0 0 0 X
X
Game3: LLLLLW
Progression: 1-2-4-8-16-32...
A SHORT RNG session: WLWWWWLLWLLWLWLW +54U