Quod Erat Demonstrandum CD Key
PC price comparison · Ad Dominum Games · Nov 12, 2026
Discover the challenging fun of validating logical proofs, beginning with simple propositional calculus and ending with complex, multi-domain predicate calculus. Prove yourself to be a master of logical thinking!
Lowest final price
at Steam · Standard Official
Historical low: $2.63 on November 13, 2026
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Quod Erat Demonstrandum price history
Historical lows by store
- Steam$2.63
About Quod Erat Demonstrandum
Every argument begins with set of premises that, if true, necessitate some conclusion. Your task is to prove that the conclusion does indeed follow. Given a set of premises, apply rules of inference and replacement to derive new propositions until you reach the conclusion. Each level is a proof waiting to be completed. Explore philosophical themes grounded in the works of Plato, Aristotle, St. Thomas Aquinas, and more! Though be prepared: while the levels start off easy and resemble the sort of proofs you might encounter in the wild, they soon evolve to challenge your logical thinking and pattern recognition abilities. Features 180+ handcrafted levels spanning propositional logic and predicate calculus, levels varying both thematically and mechanically 23 rules of logic — 7 rules of inference (e.g., Modus Ponens, Modus Tollens, Hypothetical Syllogism), 11 rules of replacement (e.g., Double Negation, De Morgan's Laws, Transposition), and 5 quantifier rules (Universal/Existential Instantiation and Generalization, Quantifier Negation) Gentle learning curve — 23 tutorial levels introduce one rule at a time, building from simple one-step proofs to multi-step chains Deep complexity — later levels feature nested quantifiers, multi-variable domains, and proofs requiring many steps involving complex statements Par system — every level has an optimal solution length; can you find the shortest proof? No time pressure — think as long as you need, a par score isn't needed to beat the game 60+ Steam achievements — milestones, rule mastery challenges, and other fun achievements for completionists Cloud saves — pick up where you left off on any machineRead more
Quod Erat Demonstrandum system requirements
Minimum
- Requires a 64-bit processor and operating system
- OS: Windows 10
- Processor: 1.6 GHz dual-core
- Memory: 4 GB RAM
- Graphics: Integrated graphics
- DirectX: Version 11
- Storage: 500 MB available space
- Sound Card: Any
Recommended
- Requires a 64-bit processor and operating system
- OS: Windows 10
- Processor: 2.0 GHz dual-core
- Memory: 4 GB RAM
- Graphics: Integrated graphics
- DirectX: Version 11
- Storage: 500 MB available space
- Sound Card: Any
Quod Erat Demonstrandum key FAQ
+What is a Quod Erat Demonstrandum CD key?
A Quod Erat Demonstrandum CD key is a digital code that unlocks the game on a PC platform such as Steam. After redeeming it, you download the game directly from that platform and it stays in your library.
+What is the cheapest price for Quod Erat Demonstrandum?
The cheapest Quod Erat Demonstrandum key right now costs $2.63 at Steam, 12% off the regular price. We compare 1 offers from 1 store, and the price already includes payment and service fees.
+What is the historical low for Quod Erat Demonstrandum?
The lowest price we have recorded for Quod Erat Demonstrandum is $2.63 on November 13, 2026. Check the price history chart to decide whether to buy now or wait for the next sale.
+Is it safe to buy a Quod Erat Demonstrandum key?
Buying from an official store such as Steam, GOG or Epic Games is always safe. Key resellers are often cheaper but sell keys second-hand, so check the region lock and buyer protection before you buy. Every offer on GameKeyDeal is labelled as official or reseller.
