PentaMonochord

The Pythagoreans’ foremost innovation was to correlate pitch relationships to calibrated speaking lengths of a string on a monochord. Now, for the first time, there’s an app for that!
Use IntervalBlocks to build a two-octave G pentatonic scale on the PentaMonochord using only octaves and fifths. Touch any block to see and hear its interval again, and watch the Hertz box to see how the frequencies of the two notes relate inversely to the string lengths represented by the IntervalBlock.
Touch the note labels any time to play a pentatonic tune. Press “Switch to Game” to join the Pythagorean pantheon by building the whole scale with the minimum number of steps. The Intro and the Background Information explain the monochord system in detail, and the Timeline puts it all in perspective.