"Microsoft LEGO" was one of the strangest and most secret optimizations we ever used at Microsoft, because it happened after the compiler was done, after the linker was done, after the .exe or .dll already existed, and in many cases after the developers themselves thought the build was finished.
And then, late at night, some secret internal tool would quietly take the binary apart, rearrange its organs, sew it back together, and ship something faster, smaller, and more memory-efficient than the program we had actually written.
And the best part is that almost nobody outside Microsoft knew it was happening. It’s been almost 30 years, but it’s time to tell you about it...