Editing Appendix/Ramblings/RiemannMeetsOculus (section)

===Fix Clock Inside Oculus Rift Environment===

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<font color="darkgreen"><b>Clock06.dae</b></font>:
<br />Minute (red) hand of clock is initially oriented the correct way, but it is spinning about the wrong axis.
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<font color="darkgreen"><b>Clock08.dae</b></font>:  (Oculus viewpoint)
<br />Both hands start off pointing at the same number (9) on the clock &#8212; that is, they appear to start at 9:45 &#8212; and they both move in the correct plane and both ''appear'' to be moving at the correct speeds (through the dictated, 12 seconds).  But the hands move in opposite directions:  the minute (red) hand moves clockwise while the hour (black) hand moves counter-clockwise.
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<font color="darkgreen"><b>Clock11.dae</b></font>: 
<br />My aim, here, was to construct a simpler <visual_scene> that simply contains a clock frame (no hands) at the origin, and a working clock located at (x, y, z) = (7.5, 0.0, 2.0).  I did this initially by creating two separate <visual_scenes>:  one, still named "ID1", that contains the entire ellipsoid scene but with no clock; and a second, named "ClockPractice" that only contains the clock (plus a separate clock frame with no hands).  Then inside the last set of <scene> instructions, the only specified <instance_visual_scene> was the "ClockPractice."  This worked in the Mac Preview app, but the Oculus Rift S was unable to import the file.  (Another case where zero debugging information was provided, so I don't really know why there was a complaint.)  So &hellip; I moved on to another attempt &hellip;
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<font color="darkgreen"><b>Clock12.dae</b></font>: 
<br />Here, we completely deleted the large <visual_scene> named "ID1" and simply specified the one named "ClockPractice."  I was able to load this file successfully into the Oculus Rift S as well as into the Mac Preview app.  The Mac Preview app displayed the scene as I had envisioned it, with both hands of the clock spinning counter-clockwise &#8212; this was consistent with me specifying increasing values of the spin ANGLE.  The Oculus Rift S also displayed the scene as I had envisioned it, but the two clock hands spun in opposite directions and the minute hand appeared to be spinning too slowly. 
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<font color="darkgreen"><b>Clock13.dae</b></font>: 
<br /><font color="red">This model works in both visualization venues.</font>  In the previous model (Clock12.dae), I specified only the beginning TIME/ANGLE and the ending TIME/ANGLE.  The Mac Preview correctly interpreted this to mean that I wanted all of the angles to increase linearly with time.  But, evidently, the Oculus Rift S &#8212; or, more likely, it was the KG's converter &#8212; took the shorter route to the ending ANGLE of approximately 270&deg;, that is, it went ''clockwise'' instead of counter-clockwise to get from the beginning ANGLE to the ending one.  In this new model, we have given more explicit instructions.  We have specified a total of 13 TIME values and 13 ANGLE values, so the KG's converter (or Oculus) sent both clock hands counter-clockwise, as was our intention.
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<font color="darkgreen"><b>Clock14.dae</b></font>: 
<br />Tried incrementing the ANGLE in the ''negative'' direction for both hands.  This does not work in the Oculus Rift S venue! 
<br /><font color="red">WAIT!!! Maybe if we want the ANGLE to decrement, we should always start with a large value of the ANGLE, then decrease it incrementally such that it never goes negative.</font>
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