Hey friends,
Try a max keytrack of index 64 on the wavetable "Pile Up" at a low pitch and hit some chords. You'll see how it got its name! LOL!
Cheers!
Update: After becoming more familiar with the wavetables, I see the way Pile Up got its name is because as you sweep through the table each successive wave adds a harmonic to the previous wave, a chromatic build-up as it were, and in all bell-ish tones btw.