A flexible coupling includes an input body, an output body offset from the input body, and a flexible lattice body. The flexible lattice body includes a flex beam member coupling the input body to the output body. The flex beam member has a rounded cross-sectional area with a centrally disposed minimum cross-sectional area to reduce peak stress in the flex beam member while transferring torque and accommodating misalignment between the input body and the output body. The flexible coupling is jointless, simplifying fabrication, and has a free-form geometry, reducing weight.