What elements fall in the same visual plane as the secondary focus point?
Since I want the sail boat to sit on top of the ocean, not become part of the ocean, I need to divide or separate the boat and the background water. I can do that be drawing a line on the water where the boat’s hull touches the ocean. Now the sail boat and all of the ocean in front of the boat can become a new level.
Where is the deepest point in the pattern?
Often I will move to the very back of the scene at this point to discover where the sky area lies. In a scene or landscape this can include any far off mountains, distant tree lines, clouds and the sun. For this scene the sky area contains the sky and clouds. All of the sky area lies above the ocean horizon line. There is a small jetty of land with pines that also lies above the horizon line so I will include that bit of land into my sky area.
Everything that is left becomes my background level which for this seascape includes the small harbor town and wharf. If I am working on a thin piece of stock, 1” or less in thickness, I will stop here. At this point I have four distinct levels and a sky area. As a rule of thumb I carve in the upper half of the wood surface, leaving one half of the stock to structurally stabilize my carving from excessive cupping or warping. So for a 1” thickness a four level pattern allows 1/8” per level with the sky area etched into the surface of the back half of the stock.