I am embarrassed to admit that I found the following, not through word of mouth, but on Wikipedia:
A witty anecdote serves to illustrate how the three of them differed in their approaches and relation to their teacher: it is said that had Reb Chaim [Soloveitchok] said, "This table is a cow," Rabbi Yitzchak Zev Soloveitchik would say that the table had the same Talmudic laws as a cow, Rabbi Shimon Shkop would say the molecules in a table could be rearranged into a cow, but Rabbi Boruch Ber Leibowitz would attempt to milk the table.
