I find the mechanical idea most appealing.
I’m imagining something like a barrel configuration with 3 faces that spin around a horizontal axis, with a one-way spring powered gear drive to rotate itself when the top face is depressed. Maybe that doesn’t exist yet. I’ll begin my search.
Or how about LED’s in the surface with a hand-crank generator disguised as a lazy susan underneath the board. Just spin it back and forth during analysis and it keeps the capacitor charged