if the following are true:

• expression state at time 15 = "iterate_args"
• arguments stack at time 15 = [ [ "MX", [ "Mexico", [ ] ] ], [ [ ], [ ] ] ]
• parent stack at time 15 = [ entry "MX": "Mexico", [ {"ES": "Estonia", "MX": "Mexico"}, [ ] ] ]

then parent stack at time 16 = [ entry "MX": "Mexico", [ {"ES": "Estonia", "MX": "Mexico"}, [ ] ] ]

Start from the conclusion and work back up the proof. Click the arrow to show the parents.