Smelter Sandbox — Modular Thermal Machines v4: air feeds fires, heat moves

Grid is now 0.5 m per cell and parts span several cells. Pick a part, click a cell to drop it (its top-left lands on the click) · R rotates the next placement · click a placed part to rotate it · drag it to move · right-click erase · hover to inspect. Rules: heater = hopper + 2 Compressors → +400° (scales with air) · stack = 800 + Σ touching sources · each machine splits its heat evenly between the things it touches (a heater over two stacks gives +200 to each) · pipes accumulate producers' heat (two +400 = 800), −25°/cell as it travels; an exchanger passes only its hottest input (Exchanger: 3 in one tile, 3 out the other) · stacks merge only into square blocks — 2×2 stacks = 4×4, larger squares too (T3); an L of three stays three · melt speed = temp ÷ melting point (copper 1000 · iron 1100 · steel 1500 · tungsten 3000 · xenonite 4000).