Microsoft once used its own brand of 'Lego' to optimize Windows

Microsoft used an internal tool called Basic Block Tool (BBT), nicknamed 'Microsoft Lego', to optimize Windows binaries by rearranging code for better performance. The tool addressed issues like fragmented code in large binaries, improving system responsiveness on limited hardware. Similar techniques like BOLT and HP's Dynamo later emerged, highlighting the ongoing relevance of code locality in software optimization.