Startup Idea : Wheelchair walking legs

The problem is wheelchairs don't go up stairs. Also, travelling across an uneven surface or soft sand is difficult or nearly impossible. The solution is a wheelchair with popout legs that can be deployed at the switch of a button. The legs and feet will be used when wheels are not appropriate. I picture 6 legs so the wheelchair can walk on these legs as needed. Like a spider if you will. This solves the problem of having to make spaces accessible to wheelchairs. Instead and wheelchair could easily circumnavigate steps, a beach, a cobblestone pathway.