These are the specific Achievements of Leonardo da Vinci's famous inventions for this game.
1. The Printing Press
2. The File-Cutter
3. The Viola Organista
4. The Scythed Chariot
5. The Revolving Bridge
6. The Flying Machine

In the Library on one of the book shelves you will find The Printing Press Achievement Plaque. Also there are 3 books with the contributors names listed. "A-G" "H-M" and "N-Z".

The File Cutter: After you illuminate the room with the catapult, click on the steps to get to the bookcase on your left. There on the shelf is The File-Cutter Achievement plaque.

To get the Viola Organista Achievement you need to acquire the objects to light up the fireplace first. Then turn around and scan to your left along the back wall to an alcove of skulls on the shelves. On the middle shelf is the Viola Organista Achievement Plaque.

In the back corner are some barrels next to the bridge in the cannon room. Look off to your left behind the Yurt along the wall. If you zoom in you can see the Scythed Chariot Achievement Plaque on top of the barrels.

Enter the Tower and head to the chest that is next to the Zodiac wheel. On the floor by the wood column you will find the Revolving Bridge Achievement Plaque.

In the Tower go down the stairs to the ground level of the tower. In the bookcase that is next to the fancy iron gate. Look on the bottom shelf in the wooden box for the Flying Machine Achievement Plaque.