To ascend anywhere upwards, in the absence of wings and the ability to fly, requires some form of stairs to climb.

Even a sheer rock face on the side of a mountain needs steel pegs banged in to allow one to climb it.

A gentle slope along a path leading up a grassy hill usually has certain stages, bends or twists with minor bumps and lumps, that can be looked upon as a form of stairs.

Any creative task needs to be attempted step-by-step. I remember a spiral stairway up a round turret in a castle.

We climbed once stair-by-stair.