When you look at IKEA's LUSTIGT shelf, it looks an awful lot like the old school Donkey Kong. These rails aim to achieve that look.
Start off by painting the shelves red, once dried use black paint (or a marker) to color in the side without holes. Afterwards, align and glue the rails on either end and press them down flat, then assemble.
Note: These rails were designed with large build volume printers (such as the Creality CR-10) in mind.
I did not design the ladders but they can be found here: https://www.thingiverse.com/thing:4637016
The author marked this model as their own original creation.