To make matters worse, in beat 3 of the first measure the second voice jumps down to the lower staff before rising across the gap again. This is because the top voice ascends to a bunch of octave-wide chords while the second voice falls inside those chords for much of the passage, weaving an intricate chromatic countermelody.
This example contains up to four distinct rhythmic voices at the same time, which is not uncommon in piano parts, but while the lower two voices appearing in the left hand are pretty straightforward, the upper two are more complex.
