line roulette vs curved shape

line roulette and curved shape both are nouns.

Word	Noun	Adjective	Verb	Adverb
line roulette	Yes	No	No	No
curved shape	Yes	No	No	No

As nouns, curved shape is a hypernym of line roulette; that is, curved shape is a word with a broader meaning than line roulette:

line roulette: a line generated by a point on one figure rolling around a second figure
curved shape: the trace of a point whose direction of motion changes

Other hypernyms of line roulette include curve.

line roulette (noun)	curved shape (noun)
a line generated by a point on one figure rolling around a second figure	the trace of a point whose direction of motion changes