What are the pancakes in depressions?
You might have images like those below while classifying on Planet Four Terrains.
Some people on Talk have started labeling them #pancakesindepressions . I didn’t know what was causing this terrain, so I showed these to the rest of the Planet Four: Terrains team. They think this this is a variation on the same processes that create the swiss cheese terrain. That the sediment layers have varying amounts of ice that get eroded at different rates, creating then layered surface.
I’ve post an example of the swiss cheese terrain below for reference:
Example of swiss cheese terrain
The swiss cheese terrain (see above picture), is compromised of a series of small edged pits that are caused by the uneven deposition and sublimation of carbon dioxide ice. The pancakes in depressions are a separate feature, so they shouldn’t be marked as swiss cheese terrain in the main classification interface, but if you see more images like the examples above, do mark them on talk with #pancakesindepressions
Planet Four Blog 
There are other features on the Martian landscape, which come up quite frequently. For example; #yardangs: these are topographic features sculpted by the wind and are also common in desert regions on the Earth.
For example, this post by Dr. Lori Fenton illustrates this;