Vmapper:Z requires physical re-mapping and rewiring of panels when switching from odd to even number in height about rpi-rgb-led-matrix HOT 2 OPEN

+    // because the panel you plug into ends up being the "bottom" panel and coordinates
+    // start from the top panel, and you typically don't wire the bottom panel (first in
+    // the chain) upside down, whether each panel gets swapped depends on this.
+    // Without this, if you wire for 4 panels high and add a 5h panel, without this
+    // code everything would get reversed and you'd have to re-layout all the panels
+    bool is_height_even_panels = ( matrix_width / panel_width) % 2;