[Source] Lasota is a secondary character in The Witcher 2: Assassins of Kings. He is a merchant, craftsman, and dice poker player who can be found in the first tent northeast of the main entrance to the Kaedweni camp during Chapter II. If you beat him during the "Poker Face: Kaedweni Camp" quest, he'll give you the option of taking gold or one of three crafting diagrams: leather, hardened leather, or studded leather. Note that while the dialogue seems to indicate that you will get the armor diagram, you only actually get the diagram for the material itself.