Century Plant Triplets--3rd Week Higher Up

The pixstrip shows the agave triplets pic from March 11 and March 18. Do a visual comparison of heights of the plants between the picture on the left and the one on the right. The increased height looks to be about the height of the sign on the right. Read the entire article at http://whilldtkwriter.blogspot.com/2013/07/century-plant-triplets-3rd-week-higher_28.html and comment there, please.