Ok I've just stumbled upon this and I think it's got grail-ish traits, and who'd've thunk it, but it's a 24 number system.
Based on double streets, line them up in 3 rows.
You can go 2 rows but I go 3, up to you though. Now follow each column vertically and our trigger is when you get 2 double streets repeat 4 times then bet the remaining 4 DS. If lose then keep tracking until you come round to that column again or if any other triggers appear. Essentially, yes it's waiting for a dozen to appear 4 in a row and then betting against it, but with DS you get more triggers.
Enough of my blabbing, here is a random sample
4 3 2
4 6 5
3 6 1
1 3 4 column 2 is a trigger, 3663, bet 1245
5 2 3. Win, wait for next trigger
1 5 6
1 6 6 trigger column 1, 1511, bet 2346
5 2 3
4 1 5 win
2 5 4
3 6 2
3 6 4
2 6 1 triggers in both column 1 + 2
2 3 1. Loss in column 1, win column 2. Both columns still are triggers as only 2DS in last 4 outcomes
5 3 5. Win, loss. Column 2 is still trigger, bet 1245
5 3 5. Loss, all 3 columns are triggers.
4 5 5. Win, win, loss. Column 2 + 3 are triggers
5 6 6. Win, win. Columns 1 +3 are triggers
3 2 5. Win, loss. Column 3 is trigger
1 4 1. Win. That was a very intense period of play, is usually quieter!
6 6 5
6 1 2
4 1 3
1 6 3 trigger column 2, bet 2345
4 3 5. Win
5 3 6
6 4 6
5 6 6. Trigger column 3, bet 1234
4 6 1 win, trigger column 3
5 3 1. Loss, column 3 remains a trigger still
2 6 5. Win, column 2 is new trigger
2 6 1. Loss, column 2 + 3 triggers
3 6 6. Loss, win, column 2 trigger
Etc
This works because when one column isn't going for you, there's another that bails you out. I think a 1,3,9 or go home would work with this . Outlay is slightly more due to the 4 DS but hit rate is great and consecutive losses not many.
Test to your hearts content and make some moolah!
BW
You write the results as they come from left to right in rows of 3 then go down to the next column?
That's right RG.
If you;re not sure then give me some numbers or as DS numbers and I'll run through them
BW
Here is a tough session, but still no more than 2 losses in a row with this beauty,
4 3 1
3 3 3
6 6 6
6 6 6 Trigger column 2
6 5 3 win, trigger column 1
3 1 1 loss
6 6 4 loss
4 5 5 win
4 4 2
3 5 5
3 3 1 trigger column 1
3 5 6 loss
5 6 5 win, trigger column 1 still
2 5 4 win
6 3 1
1 5 6
1 3 2 trigger column 2
3 3 2 loss
2 1 3 win
4 6 4
2 2 2
5 4 3
6 4 1
3 1 2
5 5 6
3 4 3
3 1 6 trigger column 1
5 5 3 loss, trigger column 3
3 4 2 loss, win, column 1 still active
2 5 4 win
4 5 3 trigger column 2
2 6 2 win
somethin about writing them left to right but playing vertically ;)