Spent a year building a financial analysis engine for automated commodities trading, including a home-baked distributed computing system. Ran it on servers at w

Spent a year building a financial analysis engine for automated commodities trading, including a home-baked distributed computing system. Ran it on servers at work (which was unethical) and ended up losing some money (not a lot) on trading a system it produced. The trades themselves did make profit, but I failed to account for broker fees. Good learning experience but wasted a lot of time writing code that I ultimately threw away.