Vertical view: Starting from the most recent draw, look up from the bottom to trace back to the first draw of the Double Color Ball. This method of number selection is mainly used to investigate the history of the winning numbers of the Double Color Ball and establish a record for them. This way, when there is a need to fill in the blanks in the records, timely judgments can be made. 1. Historical Numbers: A statistical chart of the numbers drawn in the history of the Double Color Ball and related sales volumes.