With Bracha Krohn:
"Women in Jewish Law"
'We discussed the idea of the need for fences around certain mitzvot to protect them from violation. In that context, we began learning about the Rabbinic prohibition "yichud" - i.e. that we cannot be alone in a closed or secluded place with someone who is forbidden to us from the list of Gilui Arayot (Vayikra Ch. 18)'