Century Plant Triplets--6th Week Subtle Continued Growth, Gauging Heights

The pixstrip shows the agave triplets pics from April 2 and April 8. At first glance, they don't seem to have changed much. I have, however, included height guestimations by using a street sign height and estimated people height as initial reference units of measure. Read the entire article at http://whilldtkwriter.blogspot.com/2013/08/century-plant-triplets-6th-week-subtle.html and comment there, please.