The Quote

You have the book for one trading day. Each round you set a real quote — how wide, and which way you lean it — and the flow is then simulated against it: noise orders sweeping the book from the touch, informed orders that take your price precisely when your price is wrong, and a queue that decides which of them ever reaches you. Quote inside the touch and everything fills you, including the trades you did not want. Join a fat level and you will not trade at all. It opens quiet, with the spread there for the taking. By the close you will be carrying a position you did not choose, into a market that is moving.

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CapitalYour P&L cushion, in points. Every fill and every tick of carry marks against it. Zero → the desk stops you out.

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P&LRunning trading P&L. 50 is flat; capture the spread to build it, get picked off and it falls.

🎩

Desk standingHow close your quote was to the best one available on what you could see. Not the same as the money. Zero → they take the book off you.

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InventoryPosition carried against your limit. Past 100% the risk desk force-flattens you into the worst of the move.

Your quote is two numbers. Everything that happens next is arithmetic.