5.2. Other Examples. We can apply this idea also on a few other circular ring patterns. For instance the second pattern of display A can be transformed into two interwoven layers (Figure 18). And the third drawing of display A can be transformed into four interwoven layers (Figure 19). The number of layers corresponds to the minimum number of colors mentioned by Escher.
Figure 18: Two interwoven layers
Figure 19: Four interwoven layers

5.3. Holes, tiles and rings. The pattern of the four interwoven layers can now be transformed into a well-known tiling. Making the holes in the layers as small as possible brings us to the pattern of Figure 20c. And now we can interpret the convex arcs of each tile as the upper part of a circular ring (Figure 21). So the tiling can be seen as a drawing of entwined circular rings, not laying flat in a plane as in Escher's display but as a three-dimensional structure.
Figure 20 a,b,c: Holes, tiles.
Figure 21: Three Dimensional Ring Structure.