STAIRS and STEPS...

 monuments to movement

Basaltic Stone Steps with recessed aggregate joints with four inch risers.
Note form and function in the continuity of material handling, in sculpting multiple use surfaces from the same load of quarry stone: 
Patio, Border, Tree-well-wall, Stairwell, Landings and Step-stone-path.
basaltic stone pathway
Choosing the appropriate stone quarry to supply your project is well worth the time it takes to vet them.  Note the Variation & Veining in  choice of stone, compared to the black basalt.  Both with their unique moods. Also note the Difference in Joints i.e. an open vs mortar filled grout joint.
When stonework becomes too costly. or when you would like to vary the aesthetic of the material, Key the Stone Wall into a modular block run.
Like Pathways, Stairs connect our outdoor spaces.  
Unlike a Path they require vertical lift between places, whether it is one step or a flight of sixteen.  
Cadence, tempo and rhythm are often overlooked as design opportunities.
 
The act of walking is actually an act of consistently maintaining balance, while falling on your face,
(that is why a toddler has such a rough time of it). 
Moving up or down a stairwell exacerbates this experience.
As designers we are tasked with minimizing potential falls.  The main rule of thumb is a consistent 'rise and run' ratio of each step, as it relates to the next - 
a predictable rhythm, cadence and tempo.
 
Rhythm, can be considered here, a pattern of controlled repetition, in terms of how one's footfall relates to the previous one.
 
Cadence is more of the measure of movement, its beat, or the number of footfalls per minute, experienced mainly in the lift of the foot.
Tempo is the speed of those steps, for example, the number of steps per minute.
It never ceases to amaze me how, deep down in our monkey brains, we take all of these 'measures' into account, while we are hopping up against gravity, or bopping down with it.  Somehow we manage.
 
As designers and builders of such monuments to movement, it is important to keep these more subtle considerations in our toolkit.  And, in that spirit, let us move on to the more pragmatic and 'eye candy' aspects of building a stair.
Generally, the rise of a stair is four to eight inches, depending on the terrain and use.  The tread is generally no less than eight inches.  Personally, I prefer a six inch rise to a twelve to eighteen inch tread; again, there are also many topographical and usage aspects to consider.
Ergonomics of the human body is our reference point of departure - 
the average 'measure' of movement of an adult.
oK - more on this later; perhaps, I should section off these types of discussions for you more, academic souls? Let's return to the 'visual'.
Lacing a Path though the landscape is generally preferable to a straight shot, particularly when you have existing elements, such as trees, to wind though.
This upward sloping path, that winds around the home, is structured with a cadence between sections of path,
steps, then path once again.  Note that it could arguably also be designed as a 'stramp'-path.
This is another opportunity to consider and apply:
Cadence, Tempo and Rhythm to such decisions as to what happens where.
 Brick Stairwell with four inch risers. 
Shallow steps, such as these require a more generous tread depth, in this case three time the riser height.
Note the thick Concrete Base; you are actually building two scaffolds of stair, one in concrete, the other in brick.
Brick spacing to accommodate grout.
It is necessary to Cut Brick when needed to conform to the modular layout; particularly, when doing a 'work-around' of existing landscape edging and borders.
Grouted Brick prior to acid etch.
A lot of mortar and brick cutting debris is part of the job.  After cleanup the brick is best served with a Wash and brush of Muriatic Acid.
Railroad Ties drilled and set with rebar stakes.
A relatively inexpensive stairwell, savings in both skilled labor (as for above masonry) and in costs of materials.
Eventually, the ties will chip, decay and rot-out.  But, they do the job of getting you from point A to B for a long time.
They can be cut to length to jog around existing landscape elements as well.
When working with railroad ties, if the Rise to Run Ratio allows, install double deep treads.
Steel Wrap around Riser with Compacted Aggregate Tread.
I developed this stair system in response to creating a durable replacement for railroad ties.
In addition, it is also extremely affordable as well as relatively easy to install.
They are built-to-suit, so you can adjust their dimensions to fit your site's and personal requirements.
In addition, the steel can be powder-coated for color, if so desired.
Curvaceous stairwell in steel. 
Note that these two steel stairwell pics are from two different installations - most notably seen in the texture of the compacted aggregate tread.
Note that you are not limited to this 'earthen' tread.  The steel wrap around riser could be used as an in-place form for a colorized concrete pour.  Stone, pavers or tile could also be utilized.  It is a very versatile system (Kimberly).
Camouflaged coloration:
 
Another appeal to this earthen and steel stair design, is how it disappears into the landscape.  
The compacted aggregate treads are composed of the same material utilized in the earthen pathways that link them to open space.  Steel edging is also used as a containment border for such paths, further complementing the stairwell.
Should you want the stairwell to contrast the landscape instead of this complementary design, simply utilize an aggregate of a more striking coloration.  As mentioned earlier, the steel risers can also be sent out for powder coating coloration prior to installation.