Suggestions for sketching a vertical egg for the fall equinox are as follows:

1. Draw an egg: first, start drawing an egg shape. You can draw an ovoid shape, but keep in mind that one side of the egg will usually be slightly flatter than the other. Find a balance point, at the bottom of the egg, and try to find a balance point that will allow it to stand upright. This is a key part of the process, and you can draw where the egg will be at that point.

2. Draw some decorations: you can add some decorations on the egg, such as some patterns, motifs or colors. This can make your sketch more interesting. Mark the date of the autumnal equinox, if you want to emphasize the tradition of erecting eggs on the autumnal equinox, you can mark the date of the autumnal equinox (usually September 22 or 23) in your picture so that the viewers will know your theme.

3. Light source and shading: Consider the direction of the light source and add some simple shading to the egg to add dimension to the painting. Usually, the light source comes from above. Consider whether you want to add a background to provide a sense of the environment or scene. You could paint some grass, sky, or other elements.

4. Practice and experiment: Don't be afraid to try multiple times and experiment with different styles and techniques each time until you are satisfied. It's fun to create, enjoy the process and be as creative as you want.

Principle of the Autumn Equinox Egg Standing Up

1. The principle of the Autumn Equinox Egg Standing Up is actually a myth and has nothing to do with the day of the Autumn Equinox. The ability of an egg to stand upright does not depend on the date, but on a number of other factors, such as the shape of the egg and the tiny unevenness of the surface. Usually, one side of the egg is slightly flatter than the other, which causes the egg to stand up more easily on one side.

2. When you gently slide the egg and find the right balance point, it will stand up and not fall down. This is not because of the particular position or date of the earth, but simply a matter of the egg's own properties and balance.

3. The idea of erecting an egg on the fall equinox is a superstition or traditional misconception that has nothing to do with the Earth's equatorial position or date. You can try to erect an egg at any time of the year, and as long as you find the right balance, the egg will stand up.