A seamless, flat pixel art texture of a steel I-beam, designed to represent the surface texture of a structural steel beam. The texture should have subtle metallic tones in gray, with slight shading and simple lines to indicate the flanges and web of an I-beam structure. It should look industrial and weathered, with minimal rust or wear, and be loopable for tiling across surfaces. Perfect for low-poly models and SketchUp, with 128x128 resolution for pixel clarity, no 3D effects or background.