Every hill in this scene is a torn edge. Drag the picture to move the layers apart and see how shallow the world really is.
Cut paper dioramas have been made for four hundred years. The technique is unchanged: draw the nearest shape, cut it, mount it a few millimetres in front of the next, and let the gap do the work of depth.
Only the silhouette of the closest layer is visible, so only the silhouette needs to be beautiful. Everything else can be implied.
A torn edge keeps the fibre of the sheet and catches light unevenly. It reads as landscape; a cut edge reads as paper.
Four millimetres between layers is enough. The eye supplies the rest, and the world becomes as deep as you are patient enough to build.
A single warm source at a low angle turns seven flat shapes into a valley, a forest and a sky.