This system for betting on roulette covering the entire board:
1. 1 on low (1:1)
2. 1 on 3rd dozen (2:1)
3. 1 on first col (2:1)
4. 1 on 20-24 (corner) (8:1)
Bet D can be switched to 13-18 (represneted by 'd', a 5:1 bet)

This is a bit confusing at first to look at, consider the following diagram. Each bet is displayed

```+---+---+---+          1:1 2:1 8:1 5:1 bet
|AC |A  |A  |  A   -> (+2              -4) == -2
+---+---+---+  AC  -> (+2  +3          -4) == +1
|AC |A  |A  |  BC  -> (    +6          -4) == +2
+---+---+---+  B   -> (    +3          -4) == -1
|AC |A  |A  |  D   -> (        +9      -4) == +5
+---+---+---+  C   -> (    +3          -4) == -1
|AC |A  |A  |
+---+---+---+  d   -> (            +6  -4) == +2
|AC |A  |A  |  Cd  -> (    +3      +6  -4) == +5
+---+---+---+
|AC |A  |A  |  D odds:
+---+---+---+  win  (AC, BC, D): 1/3
| Cd| dD| dD|  loss (A, B, C):   2/3
+---+---+---+
| Cd| dD| dD|  d odds:
+---+---+---+  win  (AC, BC, d, Cd): 16/36 (4/9)
|BC |B  |B  |  loss (A, B):          20/36 (5/9)
+---+---+---+
|BC |B  |B  |
+---+---+---+
|BC |B  |B  |
+---+---+---+
|BC |B  |B  |
+---+---+---+
```