Engraving refers to creating definition through space. For example, a doorway has no substance; it is defined only by space, by what is not there. Carving, on the other hand, is the mirror image of engraving. Hence, while an engraved image is defined by the space that is left through the removal of substance, a carved image is defined by the substance that remains. The two processes are complementary. On a personal level, in order to create something we first have to make a space for it in our lives, and we then carve the image in our minds. This is what happens when we "daydream" about what we want to be, and then keep refining that image unitl we become it.
"As one fantasizes in his soul, so he is. -Proverbs 23:7"
Chaos and mire refer to a state that is simultaneously beyond all structure but generative in nature. This state is superceded by void and clay which imply the formation of a space for creation to occupy and of substance that can be manipulated within this space.
There is a symmetry between engraving and carving which points to the oneness of God. For example, draw a circle in the sand, and the outside will be defined by the inside and the inside by the outside. Engraving or removing from one side is seen as carving from the other side of the looking glass. However, a truer picture is formed when we imagine doing this in water. Then we see that the inside is really the outside and the outside the inside, and God never loses His simplicity.
Through will and vision, fundamental "particles" come into being, and from these particles a world is formed. In Kabbalah, these particles are represented by the twenty-two letters of the Hebrew aleph-bet, and all that we say and all that we tell ourselves to describe the world is formed from these twenty-two letters.
To engrave them like a sort of garden implies the planting of seeds. We make a space for something in our lives, and we plant the seeds that will start the growth process. The planting of a seed is also a statement of one's will such as, "I want to learn Hebrew," or "I want to study Kabbalah." This statement of will starts a process that takes us in the specified direction.
"I am the Lord your God who teaches you for your gain, who leads you by the way that you would go. -Isaiah 48:17"
To carve them like a wall refers to the further refinement of our vision. A wall is a boundary, and as we add definition to our goal, a clearer image emerges as boundaries coalesce.
To cover them like a ceiling refers to the completion of the creative process. A covering is like a garment, and when the ceiling is installed the construction is finished.
The above refers to a three step process for creation. First, decide what you want to do. Next, start filling in the details through the visualization of a concrete plan. Finally, the concrete realization of the goal represents the garment or physical covering for the initial inspiration and the planning stages that the project went through.
Notice that we are not trying to describe above any sort of "magical something for nothing" process. Instead, we are talking about how you improve your life and the world through good, honest, hard work. For example, several years ago I woke up one morning and "knew" that it was time to go to graduate school in mathematics. The seed was planted. Next, I gathered information about applying, got letters of recommendation, chose a major university, and worked my "tuchis" off. This is the difficult but rewarding process of carving. Finally, my goal became a reality, and I put on the garment of doctoral robes to receive my Ph.D. in mathematics.
"The lazy man does not roast his catch; but the diligent man will get precious wealth. -Proverbs 12:27"