Classic 3×3 Retro. The simplest demo. Three reels, three rows, five paylines, cherries, bells, BARs and sevens. The point: every weight and every payout is right there on the right side of the screen.
This is the smallest possible transparent slot we could ship: 3 reels × 3 rows, 5 fixed lines. Each spin draws 9 symbols from a clearly disclosed weight table. Wins are evaluated left-to-right per line. There are no scatters, no cascades, no bonus rounds — just RNG, weights and the paytable.
If you want to convince yourself the math is right, run the simulator on the right. It takes a couple seconds and reports the empirical RTP.