数学老师用粉笔在黑板上画出了一个漂亮的摆线图形。

The math teacher drew a perfect ___cycloid on the blackboard with chalk.

孩子们在操场上画出的摆线图案看起来几乎像完美的圆形。

The children drew ___cycloid patterns on the playground that almost looked like perfect circles.

医生注意到她周期性的情绪波动，建议进行循环型人格评估。

The doctor noticed her cyclical mood swings and recommended a ___cycloid personality assessment.