How it works
You start with 100 points. Each trade wins with a probability of 52% and pays 1:1: a win adds your chosen risk percentage to the account, a loss takes the same percentage away. The percentage applies to the current balance, so your stake grows and shrinks with the account. You survive if you complete 40 trades; if the account falls below 20 points first, that counts as ruin. Max DD is the largest drop from a previous high, in percent.
On average every trade earns a little, yet the size of the bet decides how the run turns out. In this setup the growth-optimal fraction (Kelly) is 4% per trade. At about 8% the typical (median) run no longer grows, and above that it shrinks, even though the average gain per trade stays positive. Exact calculations for this model put the chance of ruin within 40 trades at practically zero up to 4% risk, about 0.1% at 8%, about 1% at 10%, about 12% at 15% and about 47% at 25%. Small stakes do not prevent losing streaks, but they keep drawdowns shallow enough to get through them.
The model is deliberately simple: fixed odds, independent trades, no costs and no slippage. Real win rates are unknown and change over time. The game illustrates the idea; it does not tell you what level of risk is right for you.