float lineY;
float squareX;
float squareY;
float squareSize;
color Clr;
int range;

void setup(){
size(400,200);
noFill();
rectMode(CENTER);
lineY=height;
squareSize=20;
Clr=color(255,0,0);
}

void draw(){
background(0);
stroke(255,80);
line(150,0,150,lineY);
line(250,0,250,lineY);
stroke(Clr);
line(mouseX,0,mouseX,lineY);
rect(squareX,100,squareSize,squareSize);
if(mouseX > 150 && mouseX < 250){
squareX = mouseX;
}else if(mouseX<150){
squareX = 160;
}else if (mouseX>250){
squareX = 240;
}
}