What do you see? A levitating piece of aluminium? Almost there!
Dot made this video with this video dolly.
Step 1: Get a flat rigid plane, here an aluminium PC side panel (structured)
With super limited budget and time, we needed something to make a video dolly, so a plane surface with perhaps wheels (soft ones) for a smooth linear movement. The aluminium side panel of a PC was the nearest flat element at that moment... (not with the wheels of course).