Andrews, Texas native Darren Richardson, the United States Department of Agriculture advisor for the Farah Provincial Reconstruction Team and periodic instructor at the Farah Agriculture and Veterinary Science High School and Institute, pauses during a lecture about land elevation analysis, Jan. 12, Farah, Afghanistan. Richardson relies on PRT interpreters to help him teach his Afghan students and is accustomed to speaking in succinct sentences between translations. Richardson previously demonstrated how to use a surveying level, tripod and surveying rod in a field near the campus back in October 2009. Today's lesson is the second part of that class in which Richardson showed the students how to use applied Math to understand the slope or grade of the field in preparation for leveling it.