A simple cup to prevent castor wheel fitted furniture from running about. 

A secondary consideration was to minimise the amount of material used.

Best option is to fit cups to all wheels (presumably 4) since they do introduce some additional height so your furniture could go off level or wobbly if fitted with fewer cups.

The specific application here was to prevent a filing cabinet from running off its parking patch (on a hard floor) when the bottom drawer is opened. Does the trick and helps my sanity.

Printed here in PLA.