Portions may pertain-to a tract.Logical formLearned from5 sentences. Surfaces of a vocal tract may be represented.Logical formLearned from5 sentences. Parameters may specify a size of a vocal tract by matching an image.Logical formLearned from5 sentences. A (tract shape) may be specified on a screen.Logical formLearned from5 sentences. A (tract section) can be vocal.Logical formLearned from5 sentences. A (vocal tract) may pertain-to a speaker.Logical formLearned from5 sentences. Receivers may be placed in a vocal tract.Logical formLearned from5 sentences. An area may be computed at a (tract section).Logical formLearned from5 sentences. Area can be in parts of a tract.Logical formLearned from5 sentences. A (tract model) may pertain-to persons.Logical formLearned from5 sentences. (Tract shapes) may be specified.Logical formLearned from5 sentences. Surfaces may pertain-to a vocal tract.Logical formLearned from5 sentences. Tracts can be retinal.Logical formLearned from5 sentences. Tumors may pertain-to a digestive tract.Logical formLearned from5 sentences. Viral infections may pertain-to a respiratory tract.Logical formLearned from5 sentences.