Nine Chambers
Sand RevealHave 500 practice points
Your practice points ran out. Here are 500 more, once, at no cost. Points are a scorekeeping device and carry no value of any kind.
Stratosphynx runs free simulations of online casino games. Every board follows the real rules and the real odds of the format it simulates, and is played with practice points that have no cash value. There is no real money anywhere on this site, nothing to deposit, nothing to withdraw and nothing to win.
How to play
- Set your entry and start the round. The board is filled the moment the round opens, before you touch anything.
- Press and drag across a covered tile to clear its coating. A tile counts as uncovered once enough of it is gone, and uncover the rest clears whatever is left in one press.
- The board pays for the richest symbol that appears the required number of times anywhere on the grid. Position never matters.
- Because the grid is decided before the first drag, no order of uncovering changes the result. The uncovering is presentation, and the guide below gives the probability of every outcome.
The rules
Press and drag across a covered tile to clear its coating. A tile counts as uncovered once enough of it is gone. Uncover the required number of identical symbols anywhere on the board and the round scores at that symbol's multiplier. Every result is decided the moment the round starts, before you touch anything, so the order you uncover in changes nothing.
If this is your first board
Start on the two-by-three board, where only two matching symbols are needed. Uncover every tile even on a losing round; watching how close the near-misses come is far more instructive than only looking at the wins.
Pay table
Every figure below is computed from this board's own settings, not typed in by hand.
| Symbol | Share of the pool | Pays | Probability | About once in |
|---|---|---|---|---|
| πππ | 25.9% | Γ1.726 | 42.526% | 2.4 |
| πππ | 22.2% | Γ0.863 | 18.501% | 5.4 |
| π§Ώπ§Ώπ§Ώ | 18.5% | Γ0.479 | 8.709% | 11.5 |
| πππ | 14.8% | Γ0.288 | 4.144% | 24.1 |
| π¦ π¦ π¦ | 11.1% | Γ0.153 | 1.801% | 55.5 |
| πππ | 7.4% | β | 0.591% | 169 |
The formula
for a symbol drawn with share p: chance = Ξ£k=3T C(T,k) Γ pk Γ (1βp)Tβk
the board pays only the richest qualifying symbol, so each row above is that symbol's chance with no richer one present
Long-run return = Ξ£ (chance Γ multiple) = 95.01%
The maths behind it
This is a sampling question, not a skill question. On a board of T tiles drawn from a pool where each symbol has weight w, the chance of finding N identical symbols follows directly from the pool weights. Because the outcome is fixed before the first drag, no uncovering order improves it, and the reveal is presentation rather than gameplay. Understanding that the answer exists before you start is the point of this family.
Where it comes from
The covered-panel idea is simple enough that it has been reinvented many times: print a result, hide it under a layer that can be removed by hand, and let the person uncovering it learn the answer one piece at a time. Printed versions arrived once a coating could be made that scraped away cleanly without damaging the ink underneath, and the format spread quickly because it needed no machine at all.
If this is your first board
Start on the two-by-three board, where only two matching symbols are needed. Uncover every tile even on a losing round; watching how close the near-misses come is far more instructive than only looking at the wins.