The narrative voice is bliss

At times the Gemara gets so intoxicated with its own line of thought that it just goes right ahead and ignores the Mishnah.

Halachah Is Not Esthetics
An article in Makor Rishon.

Looks interesting, but I haven't read it yet:

The traditional halachic principle which prohibits "a mitzvah done through sinning" is not all-encompassing. According to a distinction made by the Rabbis of the Talmud, it goes into effect only in the most blatant of circumstances.

Choni the Furrow-maker
A.k.a. the Plasterer. Or the Roof-smoother.

All these are alternate translations of חוני המעגל, generally known in English as Choni the Circle-Drawer. Listen to this particularly satisfying explanation of his name, from an article by Dr. Israel Rosenson.

There is a similarity between the עוגה (ugah) in this story and the עוגיות (ugiyos), round furrows around trees, mentioned in the laws of the intermediate days of festivals. "Irrigation ditches are watered during the intermediate days . . . but furrows are not made for vines" (Mishna Moed Katan 1:1).

According to this, Choni stands in the middle of the circle like a tree in the midst of its furrow-circle . . . to emphasize the dependence of a man's strength on his Creator.