I think the half curves just represent some form of travel. If you look at March 29th [1] there's a large curve for his 8 hour flight, and some small gray ones

I think the half curves just represent some form of travel. If you look at March 29th [1] there's a large curve for his 8 hour flight, and some small gray ones for walking to his gate [1] http://aprilzero.com/explorer/march-2014/29/ http://aprilzero.com/explorer/march-2014/29/