Stair climbing robot vacuum - GIF

[metric_taper]

That's useless, I wanted to see some vacuum robot that would suck all the sand and dust crap off each step, and remove any cobwebs. Seems it would be cheaper to just own as many of these as floors you think they do any decent job cleaning without a HUGE vacuum sucking that is required. Just sweeping in dirt is what these appear to do.
Oh well, this is tech not ready for my needs.