{
  "game": "coinflip",
  "displayName": "Coin Flip",
  "rtpPercent": 99.0,
  "rtpE8": 99000000,
  "engine": "uint32",
  "biasClass": "modulo",
  "params": [
    {
      "name": "side",
      "desc": "heads/tails"
    },
    {
      "name": "flips",
      "desc": "parlay length 1–20"
    },
    {
      "name": "guesses",
      "desc": "streak calls (alt)"
    }
  ],
  "maxFlips": 20,
  "sides": [
    "heads",
    "tails"
  ],
  "note": "flip_i = ['heads','tails'][u_i mod 2]. Parlay {side,flips}: win iff all match, mult = rtp·2^flips. Streak {guesses}: bust at first wrong, mult = rtp·2^wins."
}