Wanted a Citgo sign for the garage and couldn't find one already made. Inspired by @TripleGWorkshop.

Printed at 0.2mm layer height starting with white
Swap to blue at layer 6 / 1.20mm
Swap to dark red at layer 9 / 1.80mm
Swap to red at layer 12 / 2.40mm
Swap to orange at layer 15 / 3.00mm

With added white layer (helps initial red maintain color):
Printed at 0.2mm layer height starting with white
Swap to blue at layer 6 / 1.20mm
Swap to white at layer 9 / 1.80mm
Swap to red at layer 12 / 2.40mm
Swap to dark red at layer 15 / 3.00mm
Swap to orange at layer 18 / 3.60mm

Filaments used
Elegoo White PLA
GST3D Blue PLA+
eSUN Fire Engine Red PLA PRO (PLA+)
IIID Max Red PLA+
GST3D Fluorescent Orange

GST3D no longer exists, as far as I can tell IIID Max filament is very similar.