Mostly just playing around with print settings and style from this idea, https://www.thingiverse.com/thing:6533879 for clever use of Lenticular Lensing.
Made it print without supports so that it can stand on its own vertical or sideways.
Got a bit loose with the layer print peramaters - printed at 0.4mm layers and 0.8mm line width on a 0.4mm nozzle on purpose, to let the sides of the print layers work as curved optical surfaces. Pictures show the clarity of the print with the single line 0.8mm wide.
Print slow - 20mm/s.
Make sure your filament is dry.