Theory:

The poet talks about an incident that happened long ago when he himself was not available to ponder over the events that were taking place. He narrates the incident in the form of a folklore. The event is about a sage who lived long ago, in the past. The poet says that the sage, in spite of having certain norms about living a simple life, wore a handsome pigtail. A pigtail is a person's hair tied up at the back of his head. Sages are generally supposed to not indulge in beautifying themselves and are required to live a minimal life. But the sage maintains an exceptionally long pigtail. The pigtail is a handsome one, such that it is neatly combed, plaited and tied up.
 
first pigtail white2021-03-03 202341.png
A pigtail
 
The sage, unlike people who would be grateful to have a handsomely plaited hair, is worried about it instead. In fact, he is sorrowful to possess it, the reason being that it hung behind him and not in his face. This shows that wise men like sages can also be not content and satisfied with the blessings they have. When people look for perfection, the beauty is lost.
 
The sage takes this as a serious issue but considers the situation from all angles. He puts a lot of thought into the curious case. It is a curious case to him, as he does not seem to understand the reason why the pigtail is behind his head. He is keen to change the position and swears that he would have it hanging from his face and not from the back of his head. He thinks that achieving success in changing the position of the pigtail would portray him as even wiser.
 
blue man thinking2021-03-03 202602.png
The man thought of a way to change the position of the pigtail
 
After constant thinking and experimenting with his hair, he finally shouts in glee that he had solved the mystery. The lines are repeated in the poem to give an emphasis to his happiness to have solved the mystery, or rather he thinks that he has. The sage thinks that he could change the position of the pigtail, if he jumps around and turns the position of his body from the way he is standing at the moment. He therefore turns his body. But the pigtail, being attached to the head of the sage, stays in the same position. When he turns back, his head also turns back and the pigtail's positions does not change to the front of his face.
 
Man with wide arms  jumping 2021-03-03 202159.png
The sage turned around and tried jumping
 
The sage was desperate to change the pigtail's position from the back of his head to the front of his face. He jumps across the floor to see if the pigtail would appear on the front. He twists and twirls his body in a random manner to achieve this goal. In spite of being a sage, who is supposed to be wise, he does not have the maturity to understand that the pigtail is a part of his body and that human beings cannot alter the position of something attached to their body. The sage went round and round, seeing the pigtail following his rotating patterns. He then moves in and out, which is one step forward and the other backward. The poet says that it did not even create an effect as small as the size  of a pin.
 
man thinking2021-03-03 202522.png
The sage tries to bring the pigtail to his face
 
The pigtail remains in the same position even after the constant jumping. The sage probably wants to bring the pigtail to his face because he wants to see it continuously. He checks on himself to see if everything is perfect. This perfection is what forces him to twist and jump around in different directions.  He does not remain calm after one futile attempt. He then jumps right and left, hoping the pigtail would come off as it gets stretched. He then tries jumping in the normal up and down fashion. The poet repeats the words round about, up, down, left, right, out and in, so that it creates the same effect as a person moving. The poem gets the rhythm from these words.
 
The sage's sturdy pigtail hung in his back, no matter what he did. The sage was not a man to easily give up. He continues with his effort despite knowing that his attempts are in vain. He again twists, twirls and tacks, but the pigtail is faithful to the place it had remained and did not move to the face of the sage.
 
man angry2021-03-03 202641.png
The sage tries everything but in vain