"These are brilliant cards.  What a great idea and these Zwitter cards are really well made.
Congratulations Rob.
For the ‘younger’ budding biochemist you could start off with Snap where snap is yelled when the two different structures - space filling versus stick – are from the same amino acid – or indeed for all the four different card types.  Snap could alternatively be based on the type of amino acid (basic, neutral, acid), total number of carbons, or equivalent glucose balance.
Lots of fun to be had."

Prof Roy Goodacre
University of Liverpool