The figure above shows overlayed midsagittal tract shapes generated (by interpolation) during the synthesis of /da/. In the synthesis of /da/ used in this example, there are two key frames. In the first key frame, the tongue tip is raised to touch the alveolar ridge (behind the teeth). In the second key frame, the tract is in an /ah/ configuration, with the jaw dropped, and the mouth opened wide. The amount of time that it takes to move between these two key frames is determined by values specified in the control table. In this example, the vocal tract opening movement takes approximately 75 msec. During this period of rapid movement, 8 intermediate tract shapes are generated by linear interpolation (a process similar to morphing). The acoustic effect of this rapid movement can be seen in a pseudo-spectrogram, or in an actual spectrogram, or can be listened to in AIFF or AU format.