int a = 20%100;         // Sets a to 20

int b = 20%100;         // Sets b to 20

float c = 75.0%100.0;   // Sets c to 75.0

float d = 275.0%100.0;  // Sets d to 75.0

float a = 0.0;

void draw() {

  background(204);

  a = (a + 0.5)%width;

  line(a, 0, a, height);

}