no need to use 'the' in the title
set fig.width and fig.height to be 5 in the global options
no need to draw the main titles
tweak chunk options: 7in is too large; set the interval to be .1
30 images is good enough for the animation
further tweaks of the code, e.g. pause for .1 second
set the random seed for reproducibility
strip white spaces
revise the text
zoom into the rgl plot a little bit to make better use of the white space
use the 'figures/' directory for ordinary users; only I use the figure/ directory for sync'ing images

this make is much faster for me to preview the site, otherwise jekyll has to copy the mounted directory figure/
remove "the" in the filename
must not cache this chunk
add a tag rgl
rebuild the website