Cal. Elections Code § 13231

If the elections official of any county finds it necessary in connection with the use of any approved method of vote counting, the elections official may provide for any of the following changes in the format of ballots in one or more precincts at any election: (a) Ballots may be bound and padded at the side. (b) The left and right edge of ballots may be trimmed to the edge of printed material. (c) A series of punched holes may be provided in the upper right-hand portion of each ballot. (d) The ballot number may be placed at any place along the top left-hand corner of the ballot. (e) A cutout section, not to exceed two inches in depth, commencing at the left-hand edge of the far right column of the ballot, may be provided along the top edge of the ballot. (f) Press perforations may be placed between columns of the ballot, from top to bottom, to permit the folding of the ballot at each perforation. (g) “Yes” and “No” columns where necessary, may be as narrow as one-quarter inch wide. (h) The instructions to voters may be placed at the bottom of the ballot instead of at the top of the ballot, and an appropriate reference to the location of the instructions may be printed in the upper right portion of the ballot. (i) The ballot serial number may be placed on any position of the ballot that does not impact other required text or voting targets on the ballot card.