Loops are enclosed formations and therefore can be round, ellipticic and even angular shapes, including triangular.
Immediately you may think of upper and lower loops because loops jump out. However, loops can show up many places.
Sometimes loops in extenders are described as "imagination." While that is true you might also term it "expansiveness."
Here is one illustration: if you see a lower y extender that looks like a straight stick with no loop there is no expansiveness. If that is consistent throughout the sample in every y letter and all other lower strokes have no loops there is no expansiveness.
The writer is not able to come up with ideas to try different ways. He deals with matters factually. So resourcefulness and innovation are not natural gifts. He may get along just fine and get the job done anyway.
Remember, we are addressing only one area of the person's life. So, it would be wrong to say the writer totally lacks imagination. He well may have it in other areas like, in his thinking processes. If that were so, because he shows expansion in the theoretical or conceptual area of thinking, (the upper zone) he might be able to come up with fresh inventive ideas but not be able to execute them if he is lacking in material imagination (loops in the lower zone.)
To sum up: theoretical, conceptual, inventive imagination shows in the upper zone. Material, concrete, material, practical imagination shows up in the lower zone. Anyone can have one without the other. Or both kinds can show up with one being stronger than the other or possibly even quite equal when measured.
For more on loops and illustrations see the article under the category of "Global Traits." It is a good overview of the importance of identifying where imagination is found and what it means.