… a function in Cubase Atari(!) that tracked your realtime playing tempo, sort of. I vaguely remember it as a well intended but temperamental feature that more often than not goofed out leaving you in a puddle of frustration! 
I think I had it up and running for several minutes a few times. I also think I used a sustain pedal to tap with my foot. It’s all really distant so I’m probably talking out of my shoe.
Anybody interested in having that back with 2012 tech? Stable and working, of course! 
I had several live models I used onstage. They’d play guitar and shout “Slow down” or Speed up" at me when they got lost.