Train the intervals you miss.
Ten-question rounds ask you to name intervals and chord qualities by ear. Every answer lands in a confusion grid — rows are what was played, columns are what you picked — so the pairs you keep mixing up light up. Practice is then built from those crowded cells instead of a fixed random list, and tapping a cell starts a drill on that one pair. Everything runs offline; the tones are synthesised on your device.
Something not working, or an idea for the app? Email eargrid@doesonejob.com and include your device model and iOS version — we read everything.