None of these people took the reading. The record of each shows the shape.
Larry Stewart (1948 to 2007)
For more than twenty-five years, Larry Stewart, a businessman in the Kansas City area, went into laundromats and thrift stores at Christmas, handed $100 bills to people in need, and left without giving his name, which he made public only in 2006. Many small acts, each finished on the spot for the stranger in front of him and none of them signed, show the shape from outside.
Sources: nbcnews.com, en.wikipedia.org
John Jarndyce (fiction)
In Charles Dickens's Bleak House (1853), John Jarndyce keeps clear of the family lawsuit that ruins others, gives a home to three young people, pays two of them back the night he learns they covered a friend's debt, and turns away every attempt to thank him. Help given to the people within reach, finished when it is handed over and never discussed afterwards, shows the shape from outside.
Source: gutenberg.org