Mich. Comp. Laws § 168.569: Official primary ballots; numbering; separation of columns.

Sec. 569.

The ballots for each election district shall be numbered consecutively in the manner provided for the preparation of ballots for general election. Said ballot may be in 1 or more columns as may be determined by the board of election commissioners preparing the same. If 2 or more columns are used on the ballots, the columns shall be separated by a heavy black line.