This image is a wonderful metaphor for the assimilation of knowledge.
The Torah tells us that when God chooses people to construct the Mishkan, in addition to selecting Bezalel and Oholiav by name the Torah tells us that, ובלב כל חכם לב נתתי חכמה -- "and in the hearts of every wise person I have placed wisdom." (31:6). Why would God need to place wisdom in the heart of someone who is already wise? The Gemara in Brachos (54a) provides the answer:
Said Rabbi Yochanan: The Holy One Blessed be He only gives wisdom to one who already has wisdom, as it is written, "He who gives wisdom to the wise and understanding to those who have intelligence (Daniel 2:21). Rabbi Tachlifa of the West heard this idea and repeated it before Rabbi Abahu, who said to him: You learn [this rule] from that verse. We learn it from this verse, as it is written, "And in the hearts of every wise person I have placed wisdom."Yet, this only begs the question: why give wisdom to the wise? Why not spread the wealth? The answer lies in our bottle of rocks. As wisdom and knowledge increases, the information becomes finer and more specific. In every discipline, the greater your understanding of the matter, the finer the information becomes. More importantly, one cannot possibly comprehend the fine, specific information before he acquires the general principles.
This rule especially applies to Torah. To become great in Torah, one first needs to be grounded in the basics. You cannot comprehend the depths of gemara before you learn mishnah, and you can't learn kaballah (hidden mysticism) before you have a deep knowledge of Torah.
But the beauty is, the more you know, the more you realize that there is to learn.