Processing 1 – implemented :-)

This is the colour code, why not.. 🙂

void draw(){ fill(255,125,125); // fill vor the rect like stroke for the line rect (0,0,width/2,height/2); fill(255,125,0); rect (0,height/2,width/2,height); fill(125,125,0); rect (width/2,height/2,width,height); fill(0,50,0); rect (width/2,0,width,height/2); fill (255,255,0);

if (mouseXheight/2) rect (width/2,height/2,width,height); else rect(width/2,0,width,height/2); }

good night and good luck
Christian