Young man performing a skateboard trick on a sidewalk in a city.
A young man is perfoming a good skill on a skateboard on the sidewalk in a metropolitan area.
"A young man is performing a good skill on a skateboard" is a rephrasing of "Young man performing a skateboard trick"
A trick is a skill to be performed.
Skateboard trick is a rephrasing of good skill on a skateboard, and city is a metropolitan area.