The tool that finally separates the two things a tape machine always glued together: time and pitch. Stretch a sound to twice the length with the same pitch, or shift it up an octave in the same length. The trick is phase: the STFT is run at one hop for analysis and a different hop for synthesis, and each bin's true frequency is recovered from how its phase advanced between frames, then re-accumulated at the new spacing so the grains still line up. Pitch shift is just a time-stretch followed by resampling. Rendered offline (length changes, so it can't be a 1:1 live effect), then played back — press render after changing the controls.
Stretch changes length, not pitch. Pitch changes pitch, not length. That independence is the whole point.
render, then play the result with your keyboard (a s d f …) or loop it