Using the piano
Use your computer keyboard or click on the piano keys to play the piano. The top row of letters on your keyboard correspond to the white keys, and the row of numbers correspond to the black keys. You can play multiple notes simultaneously.
Click "Hide note names" above the piano to hide the note names. Click "Mark" to mark notes on the piano when clicking on them. Play the marked notes by clicking the "Play" button or by pressing the spacebar on your keyboard.
You can save your markings on the piano by copying the web address in your browser window. This also allows you to share your markings with others. For example, here is a F minor seventh chord and an E major scale.