Library/Memory automata/2PDA 2PDA · Recursively enumerable two-stack handoff @thethinkmachine·version 1·CC BY 4.0·added 28 Sept 2026 The textbook Two-Stack Pushdown Automaton example. Open in AutomataStudio More ▾ Open in the desktop app Download the .automaton file Source on GitHub q0q1q2acc The machine as drawn — 4 states, 3 transitions.