Sometimes, your project calls for some quick and dirty stairs, for access to a building site, rustic cabin or for temporary access.
A few lengths of re-bar, some 2x6 lumber, and a lot of sand and rocks for back fill will fit the bill for this purpose. These are sturdy, easy to build and equally simple to disassemble when they will be replaced.
The perfect situation will be somewhere that has sandy and rocky soil; this just makes it easier to dig out and build the stairs, and also gives you the back filling material.
Figure out how many stairs to build; they should be fairly widely spaced, with each tread being 45-60cm (18-24", and a rise of 15-20 cm (6-8"). They should be about equal in height; nothing creates problems more than having one step that is much higher than the others, and constantly trips you up.
These are not a permanent way to build stairs, just something that will allow access for now.
The soil here is a sandy clay, with a tendency to tighten up incredibly when dry, but fairly easy digging when damp.
With a dry spell in the forecast, it was getting critical to build these so that the soil would firm up into a consistency resembling concrete.
Re-bar or reinforcing rod used to make concrete stronger is used to hold the lumber in place.
A copper plumbing loop is used to hold the re-bar stable, screwed into place.
These stairs will last several years; however, since in this case the lumber is not treated (which would last longer) and is already aged, they may only last one year.
Use your discretion when utilizing this quick and dirty method of stair building, and use the materials to suit the project.
Update: although it's only been a week since I finished these steps, I've already planted Jovibarba and Sedum along the sides, ready to soften and fill in the crannies between the rocks. After a good rain or two, the plants will start to grow.