"The inhabitants of Chelm are said to be a hopelessly dull-witted lot, and a Chazan (Cantor) is, more often than not, characterized as a swaggering fool, and among the domestic fowls the turkey is seen as strutting stupidity itself.
We now have the turkey of the Chazan of Chelm before us and we want to cage him in so that he won’t escape.
All we have to do is draw a chalk circle around him. The turkey will be convinced that it is an impassible barrier, and he won’t even try to get out.
He will be imprisoned by his own folly.
Were he ever to cast doubt on its imperviousness, there would be no problem about his freedom.
It is a barrier only so long as he believes it to be real.
For man, the chalk circle is our encirclement by all of our worlds.
This barrier consists of the sense of great distance between the soul and its Divine source."
From In the Beginning by Rabbi Adin Steinsaltz , p. 215