Dwarf5 mutants and methods of using the same are disclosed. By means of the Cardanic located clamping rings, the clamping force F generated by turning a clamping screw is distributed uniformly on the spindle flange. It is less affected by protein binding, so it has a satisfactory in vivo activity. Related systems allow those with various disabilities to develop and check voted ballot forms that are substantially indistinguishable from those voted by other voters.