Mirror Subsequences: Rules and Virtual-Coin Demo

Mirror Subsequences draws two independent uniform two-digit tickets from 00 to 99, retaining leading zeros. The four digits are concatenated in ticket order. The score is determined by L, the length of the longest palindromic subsequence, which retains position order while allowing deletions. It does not use contiguous substring length.

The raw score is calculated as max(0, L−2). One whole captured stake covers both tickets. Players choose between three modes: score, score squared, or score cubed. Each mode is separately normalized over all 10,000 equally likely ordered ticket pairs to achieve a 96% expected gross return.

Crucially, the selected power does not alter which ordered ticket pairs score zero. The gross payout is calculated using the formula:

Gross = 0.96 × captured whole stake × raw^p / meanForPower(p), where p is 1, 2 or 3 and the corresponding means are 0.281, 0.301 and 0.341

The separate exact means for the modes are [0.281, 0.301, 0.341]. Expected gross return is 96%, but this is not a guaranteed net profit for a session.

The demo offers specific controls for managing the game flow:

• Stake and Mode: One whole captured stake is used; there are no independent row shares. Three separately normalized score powers are available.
• Auto and Stop: Auto mode starts at most ten draws. The Stop function cancels future draws while the current one settles.
• Settlement Timing: Settlement normally takes 480ms of animation; reduced-motion mode can settle on the first animation callback. During active settlement and the auto queue, the stake, mode, and refill controls are locked, though sound remains available.
• No Early Bank: There is no early bank feature; Stop only affects future rounds.

The wallet behavior in this demo follows specific rules:

• Initial Balance: The starting balance is 1000.
• Restoration: Balance can be manually restored to exactly 1000 only when idle and the balance is below 10. This sets the balance to 1000 and preserves fractional carry.
• Fractional Carry: Fractional carry persists across settlement, refill, and reload.
• Persistence: Settled balance persists locally, including when it reaches zero. However, an unfinished round ending on reload ends without refund or resume.

The table separates the exact expected gross return from measured sample returns. These are supporting sample observations, not the mathematical payout law or a promised return.

Note that measured RTP values are estimates and may differ slightly from the exact expected value of 0.96.

The following examples illustrate the scoring function based on the actual game.js pure score function:

• Input: [0,0,0,0] → Raw Score: 2
• Input: [9,9,9,9] → Raw Score: 2
• Input: [0,1,2,3] → Raw Score: 0

In all cases, the raw score is calculated as max(0, L−2). Powers of one, two, and three do not alter which raw scores are zero.

Storage: The source uses browser localStorage for settled demo balance and fractional carry. This does not establish anonymity or exclude other processing.

Third Parties: The template declares a Google Fonts stylesheet. Actual browser request capture is pending; this is not a claim that other requests or processing are absent.

Audience: The intended audience is 18+ based on this guide's policy, not a claim about local law or an implemented age gate. The demo has no account-login flow or payment flow, and virtual coins do not have cash value.