Polygon has what details PC maker Xi3 is revealing about "Piston," a Steam-optimized mini computer that seems to be the first blow in Valve's much discussed foray into gaming hardware. This is be a powerful little PC in a cool form factor, said to be based on its "performance level" X7A PC, a version of a modular PC that failed to achieve its Kickstarter goals last year. This seems clearly aimed at the living room and Valve's "Big Picture" initiative.