Further to the discussion by Martin in the 'show and tell' at the user group meeting on 13th March here are some associated links:
Martin's list of icons associated with variables (as of 13/03/15): https://decibel.ni.com/content/docs/DOC-41489
A short blog post: https://decibel.ni.com/content/people/Martin130114/blog/2015/03/02/labview-variables-icon-library