size(200, 200);
float value = 25;
float m = map(value, 0, 100, 0, width);
ellipse(m, 200, 10, 10);

float value = 110;
float m = map(value, 0, 100, -20, -10);
println(m);  // Prints "-9.0"

void setup() {
  size(200, 200);
  noStroke();
}

void draw() {
  background(204);
  float  x1 = map(mouseX, 0, width, 50, 150);
  ellipse(x1, 75, 50, 50);  
  float x2 = map(mouseX, 0, width, 0, 200);
  ellipse(x2, 125, 50, 50);  
}