It will be 3 terraces, each roughly 1.2 meters wide (4ft) with 30 to 40 cm (roughly 1 ft) pathways in between. Beds will be hugels as I like to do in this climate. I guess I can call them as burried wood beds, but I dont want to complicate definitions. Lets call this kind of hugels, one side burried and the other covered with sheet of wood as terrace-hugels.
Yes, I know, it is not wise to build hugels on terraces. Especially perpendicular to the slope. BUT I am a structural engineer and, yes, I made some calculations. It will hold with a safety margin triple of my third attempt. So, it is fine. If one does not know how to calculate slope stability and basic foundation engineering stuff, please don't attempt to build hugels on slopes.
My third attempt cost almost nothing. On the other hand, it didn't take advantage of the whole area and it was very labours to build stone wall and dig under the terrace level. This time, I used 1.5 meters long half inch iron pipes and 4 mm thick sheet of wood. I know, wood is going to rot probably less then 2 years. Frankly I dont care. It is so cheep and easy to build that I can change them each season in the next 20 years, and it will be less labours than my third attempt. Pipe-piles are roughly spaced 50 cms to limit deformation of wood sheets. Beds are 55 cm high, which I found to be ideal to reach ahead. I used the rule of thump to hammer the pile in twice the length that is above soil level (50 cm above soil, 1m below). It roughly costed 1500 turkish liras to build 40 square meter of growing space, so 6.25 dolars per square meter, or 0.6$/ft2. It took roughly 3-3.5 hours to transform the slope into 1 square meter (roughly 10 sq ft) of growing space by manual labour.
It is in four layers. First layer is the larger sized logs covered with green stuff. It is covered with a bit of soil and then another layer of branches and soil. The third layer is compost over soil times 2 to 3 times, which is covered with the forth layer of store bought topsoil (cheapest that I can find). The foruth layer is there just to give a nice finishing and easy planting. It is only 1 inch thick. As they tend to dry out, logs and branches should not touch sheet of wood so I left a 10-20 cm thick layer of clay soil in between.
I didn't go below the pathway level and gave a gentle slope towards it just to shed extra water to the bed below and it was easier to dig this way.
So we started digging the slope for the second terrace (so we can pile soil on to the fist ones place)
added green stuff and covered with soil
and repeated the same for the second layer
and layers of compost and soil