This graph shows relationships between:
athlete and sport events (edge is medals)
country and athletes
sport event and olympics games
Only athlete is unique. Country, sport event have affix of name the Olympics games.
This is need in order to show: how to connected the athlete and game.
You can also see which countries participated in any games.
How many sports events were on the other, or the Olympics.
Also, through the athlete can understand how many medals were in the country.