When Gemcutter Buccaneer enters the battlefield, it triggers, creating a tapped Treasure artifact token.
The Treasure enters the battlefield as a 0/0 creature with all creature types due to March of the Machines and Maskwood Nexus, causing it to die as a state-based action due to having 0 toughness.
Gemcutter Buccaneer triggers, creating a Treasure artifact token.
Repeat from step 3.
NOTE: This combo creates a mandatory infinite loop that will draw the game if it isn't interacted with.