I hold a Ph.D. and two masters degrees have attended many kinds of trainings (in person seminars, online courses, workshops, etc.) and I have never seen anyone present so much information in a few minutes.  Most of which is not presented anywhere else.  I cannot recommend this course highly enough.  Anyone interested in crystals will find it invaluable.  Anyone who likes math should take it.  Anyone who teaches math should be required to take it.