AWS was re-built from the ground up. Based on systems Amazon knew it already had and how to do better.

S3 was built from the old image hosting designs, but better.

StepFunctions and SWF before it are re-designed based on the 5 internal workflow engines that existed (and still do exist).

SQS is a re-do of AMP.

DynamoDB is a re-do of Sable.

Redshift is a re-do of their internal partitioning and querying of Oracle databases but on non-Oracle databases. Their new iteration of Redshift is designed to replicate Andes + Dryad/Cradle.