Revert "File Organization"

This reverts commit 7ea706a05af124802a4d6bbd3c3c8eba35165fc8.
Revert "Revert "File Organization""

This reverts commit bca9c3e87ac79574b627aeb2f6708fa3588b75de.
Revert "BL_Sigma"

This reverts commit c6449ed7fb77a2a0750cb22bd452e65d2cae30b6.