11/03/18 18:39:45.80
こんな感じでどうでしょうか
int a = 0;
int i = 0;
void setup() {
size(400, 400);
colorMode(HSB, 100);
background(100);
frameRate(30);
smooth();
}
void draw() {
a = a+10;
if(a > 360){
a = 0;
i++;
}
if(i>10) i=0;
noFill();
stroke(50, 100, 100);
strokeWeight(2);
arc(200, 200, 200-i*15, 200-i*15, radians(-i * 5), radians(a - i * 5));
}