The sun doesn' t shine at the same height during the year, as we are in the north hemisphere, the sun shines “lying” in wintertime contrary to the summertime. This makes it project at a different height on the wall of the cosmic room.

For example, this graph was taken in wintertime. The sunlight moves leaning around forty-five degrees at latitude twenty, so the length of the mark is not enough. The higher the sun is, the bigger the mark will be.

This was taken on February 5th , the mark is lower.

This picture is of an equinox.

This picture was taken on April 9th.

On that very 9th of April in the daytime, the sun is going down perpendicular on the south wall.