A simple free-space optics recipe for the generation and detection of the optical vortices superposition is demonstrated. For the purpose a doughnut laser beam is produced by the cracked glass plate. To control the vorticity of produced doughnut light, one can deform the cracked plate. For the generation of the optical vortices superposition and determination the vorticity of the produced doughnut light, two simple interferometry setups are employed. The experimental Sagnac interferometry setup for preparing and analysing superpositions of an optical vortex and Gaussian modes is presented. Furthermore, the superpositions of two twisted beam with the opposite topological charge numbers by an experimental Michelson-Sagnac interferometry is proposed. These simple free-space experiments are useful to the application of orbital angular momenta superpositions in the quantum cryptography and the undergraduate educations