rotating impossible square

with(x){c.width|=x.f=fillRect,translate(960,540),rotate(t*.7);for(i=5;--i;rotate(1.57)){fillStyle=`hsl(${t*9} 60% ${i*8+25}%`;for(j=99;j--;f(299,100,-400,100))f(200+j,j-300,-j,400-j)}}