1+x^2-y^2-z^2-2x+2yz=1-2x+x^2-y^2+2yz-z^2=(1-x)^2-(y-z)^2=(1-x+y-z)*(1-x-y+z)
1+x^2-y^2-z^2-2x+2yz=(x-1)^2-(y+z)^2=(x-1+y+z)(x-1-y-z)