Parallax: Dual N-Back

Parallax is a dual n-back trainer for iPhone, made by me, Connor, at CST3 Media, LLC. A square appears on a 3x3 grid while a voice speaks a letter; you respond when the position, the sound, or both match the one from N steps back. Per-channel stats (hits, misses, false alarms, balanced accuracy for position and sound separately), fixed blocks of 20 scored trials plus N warm-up, paces of 2.5/3.0/4.0 s, evidence-based level suggestions after two consecutive blocks, manual levels 1-back to 8-back, trial-by-trial review and CSV/JSON export. $4.99 one-time. No ads, no subscriptions, no accounts. Research on benefits beyond trained n-back performance is mixed; it does not measure IQ.