The public column restriction
The board has four rows and four columns. Choose 3, 4 or 5 mines. Read each column from top to bottom, with 0 meaning safe and 1 meaning mine. Neither of its two consecutive three-cell windows may contain 010: safe, mine, safe. The game draws uniformly among complete boards with the chosen mine count that meet this rule. There are 144 allowed boards with 3 mines, 404 with 4 mines and 920 with 5 mines. A safe reveal removes boards that put a mine in that cell. A covered cell’s safe probability is the fraction of remaining boards that leave it safe. Probabilities can differ by position and change after a reveal.
Stakes and available actions
Select a stake of 10, 20, 50, 100 or 200 virtual coins and 3, 4 or 5 mines. Defaults are stake 20 and 3 mines. Starting deducts one whole stake. Stake, mine count, refill and starting another round remain locked during play. Eligible cells and, after a safe reveal, Bank current quote remain available. Sound can be toggled. There is no auto queue or random-cell button.
The gross-quote calculation
Gross quote = 0.96 × captured stake × initial allowed-board count ÷ current compatible-board count. Before any reveal the quote is 96% of the stake, but banking is unavailable. A safe reveal can increase the quote or leave it unchanged if no boards are eliminated. A mine ends the round with zero gross return. Gross includes the stake; subtract it to calculate net profit.
A worked safe path
With 3 mines there are 144 initial boards. If the top-left cell is safe, 105 boards remain; its initial safe probability was 105/144. At stake 20 the quote is 0.96 × 20 × 144 / 105 ≈ 26.331429 coins, including the stake. Raw net profit is about 6.331429. With no previous carry, banking credits 26 coins and saves about 0.331429. If the first three cells of the top row are all safe, 50 boards remain and the gross multiplier is 2.7648.
Banking and the upper guard
Bank current quote is available after at least one safe reveal. The game automatically banks after all safe cells are opened or no eligible covered cell remains. Already opened and certainly mined cells are disabled. A cell is also disabled if its prospective safe quote exceeds 1,000 times the stake; equality is allowed. The largest raw multipliers for 3, 4 and 5 mines are 138.24, 387.84 and 883.2, so that cap does not exclude an otherwise possible safe transition in these board sets. The exact expected unrounded gross return is 96% of the stake for the tested stopping policies. It is not a 96% winning probability or a promised player or session result. Saved simulations are sample observations and can differ from that expectation. The demo itself draws actual random boards within the allowed set; its outcomes are not simulation statistics or outside casino results.
Whole coins, carry and reload
A new wallet starts with 1,000 virtual coins. Balance and fractional carry are stored in browser localStorage, including zero balance. Settlement adds raw gross return to previous carry, credits whole coins and saves the fractional remainder. A mine’s zero gross return leaves previous carry unchanged. While idle below 10, manually restoring sets the balance to 1,000; it does not add 1,000 and preserves carry. Reloading an unfinished round loses its state. Its stake remains deducted; there is no payout, refund or resumed round. Saved balance and carry remain, while controls return to stake 20 and 3 mines. Clearing cached files can leave localStorage intact. Removing this site’s stored data may remove wallet values.
Frequently asked questions
Are all possible layouts equally eligible?
No. Selection is uniform only among boards with the chosen mine count that satisfy the no-010 column rule.
Does a certainly safe reveal increase the quote?
No. If no compatible boards are eliminated, the remaining-board count and quote stay unchanged.
Does restoring recover a previous balance?
No. It sets the balance to 1,000 while idle below 10, preserving carry. It does not reconstruct an earlier balance.
