The cramped space makes swapping the location of working materials impossible without bond juggling. The leftover water from the first product must be stored on the right, so it must be swapped with the metal input. It must swap together with the mercury, which is why the mercury is not consumed to make copper until after the water has been swapped (and rebonded to the iron).

An earlier version had the debonder fully accessible and the bonder fully inaccessible, which was easier to work with but it was impossible for the products to reach the output without striking the debonder.

This was my first time trying to optimize for area and it was a very fun challenge. Next week's looks... rather more intimidating.