π Pi Challenge vs Sorobaco

An app for memorizing the digits of Pi. It supports up to 30 million digits… totally unnecessary, but fun. Comes with a ranking feature! Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Sorobaco is a mental arithmetic training system built around the Soroban. Not a game. Not a tutorial. A tool that observes how you think under pressure. SESSIONS Each session unfolds across three progressive phases. Phase 1: Familiarisation. The full equation is visible: 25 + 8 = 33. Learn the gestures without cognitive pressure. Phase 2: Verification. Only the question: 25 + 8 = ?. Calculate the result and set it on the Soroban. Phase 3: Challenge. Only the operation: + 8. Hold the current value in mind and apply it, the first step toward pure mental arithmetic (Anzan). Each time you lose track and reset the Soroban, a rewind is counted. Validation is silent. When the soroban matches the target, the session continues. No buttons. No confirmation. ADAPTIVE PRESSURE There is no visible timer. The system watches your hesitations and recoveries and responds. Flow in: pressure steadies. Hesitation: pressure builds. Clean sequence: a moment of ease. The time does not punish. It responds. COGNITIVE STATES After each session, Sorobaco reflects your performance through three states: Load: slowdowns, over-conscious attention, long hesitations. Flow: continuous action, stable rhythm, comfortable pace. Automatism: rapid, implicit decisions, minimal hesitation. No scores. No stars. An honest mirror. SESSIONS END NATURALLY When your hesitation pattern sustains instability long enough, the session closes on its own. No countdown. No announcement. The flow simply stops. PRIVACY No data collected. Your practice history stays in your own iCloud. No ads. No subscriptions. One optional in-app tip to support independent development.