Sonachord vs Cirquanta

Sonachord is a piano learning app with a chord-focused approach. Follow a guided path of 28 chapters — from your first notes and triads to extended chords, progressions, and ear training. You'll learn how chords look, sound, and work in real music. In the app you can: - Learn piano chords step by step - Practice recognition, recall, and progressions - Train your ear with focused exercises - Play along with the on-screen keyboard, MIDI, or a real piano - Use local acoustic detection through your microphone - Practice offline, with no account required Sonachord is a great fit for beginners, returning players, students, and teachers. Privacy: No account required. Your progress stays on your device. The microphone is used only for local note detection — audio is never recorded, stored, or uploaded. Payment: No subscription. Full access to all chapters and exercises unlocks with a one-time in-app purchase.

Make digital logic visible. Cirquanta is a native circuit simulator for iPhone and iPad. Build clear schematics, connect components directly on the canvas, and watch every logical signal react in real time. Whether you are learning Boolean logic, teaching digital electronics, or sketching a design before HDL or firmware, Cirquanta gives you a focused workspace that works offline. DESIGN ON THE CANVAS • Choose and place 60+ components from an organized library • Move, wire, rotate, duplicate, and configure elements with undo and redo • Select several parts at once, then move, duplicate, copy, or cut the whole sub-circuit and paste it into any circuit, wiring included • Organize larger designs with buses, zones, sticky notes, zoom, full screen, and curved or right-angle wires SIMULATE IN REAL TIME • Toggle switches and inputs directly on your circuit • Run, pause, advance step by step, or reset the simulation • Follow color-coded signals with deterministic four-state logic: 0, 1, unknown X, and high-impedance Z LEARN WITH CHALLENGES • Work through a 30-level campaign, from a single wire to a state machine • Follow a clear objective, with optional hints and step-by-step guidance • Earn up to three stars per challenge, graded on correctness and efficiency • Play the first six challenges free; unlock the whole campaign with Pro GO FROM GATES TO SEQUENTIAL LOGIC Start with AND, OR, NOT, NAND, NOR, XOR, and XNOR gates. Then explore multiplexers, demultiplexers, decoders, encoders, adders, latches, D/JK/T flip-flops, registers, counters, buses, clocks, LEDs, probes, and displays. PRIVATE BY DESIGN • No account and no sign-up: just open the app and start building • Works fully offline; your circuits are saved locally on the device • No ads, and your data is never sold; your designs stay yours • Optional private iCloud sync between your own devices with the same Apple Account (iCloud is never required) KEEP CONTROL OF YOUR PROJECTS • Start from a blank canvas or a built-in example • Search, sort, favorite, and archive your circuits • Export a portable backup to save or share your work Free to start with room for 3 circuits and up to 24 components each, plus six free challenges. Unlock Cirquanta Pro once for unlimited circuits and components and the full challenge campaign, with no subscription. Cirquanta is made for students, teachers, makers, and developers who want to understand or prototype digital systems. It simulates digital logic only; it is not an analog or SPICE simulator.