const kelly = p => b => stack =>
  stack * ((p * (b + 1) - 1)/b)

const bet = p => ({myStack, yourStack}) => bet => outcome =>
  outcome >= (1 - p) ?
    ({ myStack: myStack + bet, yourStack: yourStack - bet }) :
    ({ myStack: myStack - bet, yourStack: yourStack + bet })

const kellyBet = p => stacks =>
  bet (p) (stacks) (kelly (p) (1) (stacks.myStack))

const play = prec => myStack => yourStack => {
  let res = kellyBet (.6) ({myStack, yourStack}) (Math.random())
  return res.yourStack <= 0 ?
    true :
    res.myStack <= prec ?
    false :
    play (prec) (res.myStack) (res.yourStack)
}

const experiment = prec => n => {
  var you = 0
  var me = 0
  for (let i = 0; i < n; i++) {
    play (prec) (10) (10) ? me++ : you++
  }
  console.log("me", me * 20 /n, "you", you * 20 /n)
}

// try me out!
// experiment(.001)(3000)