This blanket is a tough weave, sir.

Those blood spots were woven into it by design.

The yarns were chosen from sheep and goats tried by zero weather, blizzards, undiminishing wind and hard usage.

You will not wear out this blanket in your lifetime, sir, nor mine

The weaving was done slowly; they took their time, sir; they were stubborn about the materials; just one of those accidental-looking blood spots took ten years, sir.