Pads sit on the fixed 12.5 × 9.47 mm grid of the
shipping board; the gaps are where LEDs poke through, so filling them
means rerouting light, not just pouring copper. Return path = how well
the dancer's body couples back to the electronics' ground.
What the chip sees
coupling to the hand–
baseline load (no hand)–
measured touch delta–
delta vs baseline–
Surface charge, hand present (top view)
Brighter = more charge per area. Edges and corners do
most of the work; that is why copper area is cheap on baseline. Live
boundary-element solve, coarse mesh (reads a few percent below the
committed Python solver).