(Diffraction gratings) can be periodic.Logical formLearned from3 sentences. Gratings can be periodic.Logical formLearned from3 sentences. A grid can be periodic.Logical formLearned from3 sentences. A (transfusion therapy) can be periodic.Logical formLearned from3 sentences. An interrogation can be periodic.Logical formLearned from3 sentences. An (execution tool) can be periodic.Logical formLearned from3 sentences. (Banking panics) can be periodic.Logical formLearned from3 sentences. (Postemployment benefit costs) can be periodic.Logical formLearned from3 sentences. (Stress tests) can be periodic.Logical formLearned from3 sentences. (Agency self-assessments) can be periodic.Logical formLearned from3 sentences. (Maintenance costs) can be periodic.Logical formLearned from3 sentences. Manifestations can be periodic.Logical formLearned from3 sentences. A culling can be periodic.Logical formLearned from3 sentences. (Room checks) can be periodic.Logical formLearned from3 sentences. A bill can be periodic.Logical formLearned from3 sentences.