int value = 0; void setup(){ size(200, 200); } void draw() { fill(value); rect(125, 125, 50, 50); if (mousePressed == true) { fill(0); } else { fill(255); } rect(25, 25, 50, 50); } void mousePressed() { if(value == 0) { value = 255; } else { value = 0; } }