The thieves of Venice have discovered a simple way of getting interesting weapons and fortifications.

Step 1: Fill a room with various materials and tools.
Step 2: Bribe/convince/kidnap Leonardo into coming over.
Step 3: Get the artist to overdose on the strongest version of Antonio's café they can find.
Step 4: Run for cover.
Step 5: Terrify the city guards with the new defences/weapons while Leonardo sleeps off the caffeine crash.